Exploring the gut-exercise A systematic review of gastrointestinal disorders in physical activity

Authors: Mohammed Al-Beltagi, Nermin Kamal Saeed, Adel Salah Bediwy, Yasser El-Sawaf, Akram Elbatarny, Reem Elbeltagi

Abstract

BACKGROUND

The relationship between exercise and gastrointestinal (GI) health is complex and bidirectional. While moderate exercise generally promotes gut health by enhancing motility, reducing inflammation, and supporting microbial balance, intense or prolonged physical activity may exacerbate GI symptoms, particularly in individuals with pre-existing digestive disorders. A deeper understanding of this interplay is essential for optimizing both exercise performance and GI well-being.

AIM

To synthesize current evidence on exercise-related GI disorders, exploring the prevalence, mechanisms, risk factors, and management strategies associated with exercise-induced GI symptoms.

METHODS

Following PRISMA guidelines, comprehensive searches of databases, including PubMed, Scopus, Web of Science, and EMBASE were conducted. Studies were included if they focused on exercise-induced GI disorders, encompassed randomized controlled trials, cohort studies, case-control studies, and cross-sectional designs, and addressed symptoms across various exercise modalities. Data were extracted and analyzed to identify patterns and implications for clinical and athletic practice.

RESULTS

A total of 231 studies met the inclusion criteria, highlighting both the benefits and risks of exercise on GI health. Regular moderate-intensity exercise, including activities such as walking, cycling, and yoga has been associated with improved GI function in conditions like gastroesophageal reflux disease, irritable bowel syndrome, inflammatory bowel disease, and constipation. These benefits are attributed to enhanced intestinal motility, reduced systemic inflammation, and improved gut barrier integrity. Additionally, exercise plays a role in regulating the gut-brain axis, with practices like yoga and Tai Chi demonstrating particular effectiveness in alleviating functional GI disorders. Conversely, high-intensity or prolonged exercise may contribute to symptoms such as nausea, diarrhea, and abdominal pain due to mechanisms like splanchnic hypoperfusion and increased intestinal permeability. Individual factors, including fitness level, dietary habits, hydration status, and underlying GI conditions, significantly influence the body’s response to exercise.

CONCLUSION

Moderate-intensity exercise is a beneficial and well-tolerated intervention for promoting GI health, whereas high-intensity activities require careful monitoring, particularly in individuals with pre-existing GI disorders. Personalized exercise and dietary strategies are essential for balancing the benefits of physical activity with the risk of GI distress. Further research is needed to explore the long-term effects of exercise on gut microbiota composition and overall digestive health.

Core Tip: This systematic review explores the complex relationship between exercise and gastrointestinal (GI) health, highlighting the dual effects of physical activity. Moderate-intensity exercises like walking and yoga promote intestinal motility, reduce systemic inflammation, and enhance gut barrier integrity, benefiting conditions like gastroesophageal reflux disease, irritable bowel syndrome, inflammatory bowel disease, and constipation. Conversely, high-intensity or prolonged exercise can exacerbate GI symptoms, such as nausea and diarrhea, due to splanchnic hypoperfusion and increased intestinal permeability. Individual responses vary based on fitness level, dietary habits, and underlying GI conditions, emphasizing the need for personalized exercise and dietary strategies. This systematic review underscores moderate exercise as a safe, effective intervention for optimizing GI health.

INTRODUCTION

The relationship between exercise and gastrointestinal (GI) health is complex and bidirectional, with beneficial and adverse outcomes depending on the type, intensity, and duration of physical activity. Moderate exercise is generally associated with enhanced GI function, improved gut motility, and greater microbial diversity, leading to better digestion and overall gut health. These positive effects are attributed to increased blood flow to the GI tract and the anti-inflammatory properties of regular physical activity, which help alleviate conditions such as constipation and irritable bowel syndrome (IBS)[1]. Conversely, intense or prolonged exercise, particularly in endurance sports, can induce various GI symptoms, including nausea, abdominal pain, diarrhea, bloating, and even GI bleeding. These symptoms often arise from splanchnic hypoperfusion, where blood is diverted from the GI organs to the muscles, reducing GI blood flow. This ischemic state can increase intestinal permeability, commonly known as “leaky gut”, allowing bacteria and toxins to enter the bloodstream and trigger systemic inflammation[2].

Dietary habits and hydration play pivotal roles in modulating exercise-induced GI responses. Consuming large, high-fat, or high-fiber meals before exercise can exacerbate symptoms, while dehydration and electrolyte imbalances can further aggravate cramping, diarrhea, and other GI issues[3]. Conversely, maintaining proper hydration and adhering to low-residue diets before intense physical activity can help minimize GI distress. The gut microbiota also plays a significant role in this interaction. Exercise influences gut microbial composition, increasing the diversity and abundance of beneficial bacteria, which can strengthen the gut barrier and reduce inflammation. These changes may mitigate some of the negative effects of high-intensity exercise on GI health[4].

Despite ongoing research, the exact mechanisms linking exercise and GI health remain incompletely understood. Factors such as genetic predisposition, pre-existing GI conditions, and individual microbiota variations add further complexity[5]. As such, personalized approaches to exercise and nutrition are increasingly recommended to optimize both GI health and physical performance. Understanding the implications of exercise-induced GI disorders is crucial for both athletes and the general population. For athletes, these disorders can significantly impair performance, particularly in endurance sports, where symptoms like nausea and diarrhea can disrupt competition[3]. If left unmanaged, more severe conditions such as ischemic colitis or GI bleeding may develop, requiring medical intervention and recovery time. For the general population, while moderate exercise supports GI health, intense or prolonged activity can lead to GI distress, potentially discouraging regular physical activity[6]. Recognizing and managing these symptoms allows individuals to benefit from exercise without compromising GI health. Poorly managed exercise-induced GI disorders also have broader implications for nutrition, hydration, and mental well-being. Inadequate nutrient absorption, electrolyte imbalances, and dehydration can impair physical and cognitive performance, particularly in athletes subjected to high physical and psychological demands[7]. Early recognition and management can prevent chronic GI conditions and reduce systemic inflammation linked to long-term diseases.

This systematic review aims to synthesize the current knowledge on exercise-induced GI disorders, focusing on their prevalence, mechanisms, risk factors, and management strategies. It will explore the types and frequency of symptoms associated with different exercise intensities and modalities, examine the role of dietary and hydration factors, and evaluate existing prevention and management approaches. By identifying research gaps and proposing future directions, this review seeks to provide valuable insights for athletes, healthcare providers, and the general population, fostering a holistic approach to exercise and GI health.

MATERIALS AND METHODS

This systematic review explores the relationship between exercise and GI health, focusing on exercise-induced GI disorders, their mechanisms, risk factors, and management strategies, following the PRISMA guidelines to ensure a transparent and standardized approach. A broad literature search was conducted using databases such as PubMed, Scopus, Web of Science, and EMBASE to identify relevant studies published in English. The selection of literature prioritized original research articles, clinical studies, systematic reviews, and expert opinions that provided insights into the prevalence, pathophysiology, and clinical implications of exercise-related GI disorders. Studies were included if they focused on exercise-induced GI disorders across various populations, types of exercise [e.g., endurance sports, high-intensity interval training (HIIT)], and GI symptoms (e.g., nausea, diarrhea, abdominal pain, bloating). Eligible study designs included randomized controlled trials (RCTs), cohort studies, case-control studies, and cross-sectional studies. Exclusion criteria comprised studies focusing solely on non-exercise-related GI disorders, animal studies, reviews, and editorials. Key search terms included “exercise AND gastrointestinal disorders”, “sports AND gut health”, and “physical activity AND GI symptoms”. Additional articles were identified by reviewing reference lists of selected papers to ensure comprehensive coverage of relevant topics. Studies encompassing various exercise modalities, from endurance sports to resistance training, were considered to provide a holistic understanding of the gut-exercise connection.

Data extraction and management were conducted using a standardized data extraction form. Extracted data included the author, publication year, study design, population characteristics, type of exercise, GI symptoms assessed, and key outcomes. Data management was performed using software to organize and facilitate analysis. Quality assessment of included studies was carried out using established tools. The Cochrane Risk of Bias tool was applied to RCTs, while the Newcastle-Ottawa Scale was used for observational studies. Two reviewers independently assessed each study, with disagreements resolved by consensus. Given the expected heterogeneity in study designs, populations, and outcomes, data was synthesized through a narrative approach. Where appropriate, a meta-analysis was considered to pool quantitative data, enabling a more robust evaluation of the relationship between exercise and GI disorders. A thematic synthesis approach was employed to integrate findings from different sources, emphasizing key mechanisms underlying GI disturbances, the role of exercise intensity and duration, and individual variability in symptom manifestation. The discussion integrates evidence from multiple disciplines, including gastroenterology, sports medicine, and microbiology, to highlight clinical implications and potential strategies for optimizing GI health in athletes and the general population.

RESULTS

Figure 1 presents the flow chart of the study selection process. This systematic review identified diverse studies examining the interplay between physical activity and GI health, covering various conditions such as gastroesophageal reflux disease (GERD), peptic ulcers, GI cancer, IBS, inflammatory bowel disease (IBD), GI bleeding, constipation, and diverticular disease. The included articles encompassed various study designs to ensure comprehensive insights. These comprised RCTs, cohort studies, case-control studies, and cross-sectional studies. The diversity in study types enabled a robust data synthesis, reflecting both mechanistic and clinical outcomes of exercise on GI health across different populations. The findings underscore the dual effects of exercise on GI health, with the outcomes influenced by the intensity, duration, and type of physical activity, as well as individual factors such as baseline fitness, dietary habits, and pre-existing GI conditions. Detailed summaries of the studies are presented in Tables 1, 2, 3, 4, 5, 6, 7, 8, and 9. Different factors affect the prevalence of GI symptoms during exercise, as shown in Table 1.

Impact of exercise on GI symptoms

Moderate-intensity aerobic exercise, including walking, cycling, and swimming, consistently demonstrated beneficial effects on GI health across multiple studies. For instance, regular moderate exercise improved intestinal motility and reduced constipation symptoms. Practices like yoga and Tai Chi effectively alleviate symptoms of functional GI disorders (FGIDs) by modulating the gut-brain axis and reducing stress. In IBD, moderate exercise was associated with improved quality of life, reduced fatigue, and decreased systemic inflammation, suggesting a potential protective role against disease exacerbation. Conversely, high-intensity or prolonged exercise often exacerbated GI symptoms. For instance, endurance sports like marathon running were linked to increased risks of nausea, diarrhea, and GI bleeding due to splanchnic hypoperfusion and ischemic damage to the gut lining (Table 3). These adverse effects were particularly pronounced in individuals using nonsteroidal anti-inflammatory drugs (NSAIDs) or with predisposing conditions such as peptic ulcers or ischemic colitis. Furthermore, vigorous exercise aggravates GERD symptoms, especially during activities involving bending or high intra-abdominal pressure.

Specific GI conditions

Moderate physical activity was associated with reduced GERD risk, particularly among individuals with obesity, where exercise helped decrease abdominal pressure and improve lower esophageal sphincter (LES) function (Table 2), however, high-impact or intense activities, particularly those involving bending or postprandial exercise, exacerbated symptoms. Moderate exercise supported peptic ulcer healing by reducing stress and improving circulation, while high-intensity activities posed a risk of mucosal injury. Gentle activities such as walking were recommended for symptomatic individuals. Exercise demonstrated protective effects against several GI cancers by reducing systemic inflammation, improving immune function, and promoting a diverse gut microbiota (Table 3). Physical activity was associated with decreased colorectal, gastric, and esophageal cancer risks. The protective effects were particularly pronounced in individuals adhering to recommended exercise guidelines, emphasizing the importance of regular activity.

Moderate-intensity exercise was associated with improved bile flow, reduced systemic inflammation, and decreased risk of gallstone formation (Table 4). Physical activity also mitigated risk factors such as obesity and metabolic syndrome, which contribute to gallbladder diseases. Yoga and aerobic exercises significantly reduced IBS symptoms, including abdominal pain and bloating (Table 5). These interventions improved quality of life and psychological well-being by reducing stress and modulating the gut-brain axis. However, the intensity of physical activity needed to be carefully managed, as excessive exercise could worsen symptoms in some individuals. Moderate exercise was associated with anti-inflammatory effects, improved gut microbiota, and better disease management in IBD patients. It enhanced physical functioning and reduced fatigue and psychological distress (Table 6). However, high-intensity exercise posed risks of exacerbating inflammation and worsening symptoms.

Regular moderate-intensity exercise reduced the risk of diverticulitis and diverticular bleeding. There was a significant inverse relationship between physical activity levels and diverticular complications, emphasizing the protective effects of vigorous activity (Table 7). Endurance and high-intensity exercises were linked to increased risks of upper and lower GI bleeding, primarily due to splanchnic hypoperfusion, mechanical trauma, and NSAID use (Table 8). Symptoms such as hematemesis and melena were observed in cases of upper GI bleeding, while rectal bleeding was associated with ischemic colitis during prolonged activities. Conversely, moderate exercise reduced the risk of GI bleeding by improving vascular health and reducing systemic inflammation. Aerobic exercises like walking and core-strengthening activities improved bowel regularity and reduced bloating in constipated individuals (Table 9). Notably, studies highlighted the role of exercise in enhancing intestinal motility and reducing reliance on laxatives.

Emerging evidence suggests that moderate exercise promotes a diverse and balanced gut microbiota, enhances gut barrier integrity, and reduces systemic inflammation (Table 6). In contrast, excessively high-intensity training may lead to dysbiosis and increased intestinal permeability, exacerbating GI symptoms. These findings highlight the importance of tailoring exercise regimens to individual needs and GI health statuses. While moderate-intensity exercise is broadly beneficial, high-intensity activities require careful management, particularly in individuals with pre-existing GI disorders or advanced disease. Personalized approaches incorporating dietary modifications, hydration strategies, and gradual intensity progression are crucial for optimizing both GI health and physical performance.

DISCUSSION

Prevalence of GI disorders in exercisers

**Common ** GI disorders are commonly observed among exercisers, particularly those participating in endurance and high-intensity sports. These disorders can significantly impact performance and overall well-being, with symptoms ranging from mild discomfort to severe medical conditions. Nausea, vomiting, diarrhea, abdominal pain, bloating, and GI bleeding are frequently reported symptoms, reflecting the diverse impact of exercise on GI function[8]. Nausea and vomiting are often linked to prolonged exercise, especially in hot or dehydrated conditions, where gastric emptying is delayed, leading to increased gastric distress[3]. Diarrhea and abdominal cramping, particularly prevalent among runners, are commonly known as “runner’s trots”. These symptoms are believed to result from altered intestinal motility and increased intestinal permeability during strenuous physical activity[3]. Bloating and abdominal discomfort can be attributed to excessive air swallowing, dietary factors, or accumulated unabsorbed carbohydrates in the gut. Although less frequent, GI bleeding can occur in high-endurance athletes due to ischemic damage and increased intestinal permeability, posing a risk of serious health complications if not promptly addressed[9].

The prevalence of these symptoms varies widely across different sports and exercise intensities. For instance, studies have shown that up to 70% of long-distance runners experience GI symptoms, while cyclists report rates as high as 50% during prolonged rides. High-intensity and high-impact activities exacerbate these issues due to increased physiological stress on the GI system. In a study of collegiate Division I American football players, 61% reported experiencing at least one GI symptom, with 52% noting symptoms specifically during exercise[8]. Stomach pain and hunger-related discomfort were the most reported issues, and protein supplement use was linked to higher symptom prevalence, emphasizing the significant role of dietary factors[2]. Another frequently reported condition is exercise-induced transient abdominal pain, also known as “stitch”. This pain affects up to 18% of recreational runners, with younger athletes and those consuming food or drinks shortly before exercise being particularly susceptible[10]. Understanding the prevalence and patterns of GI symptoms in athletes is essential for developing tailored prevention and management strategies. Table 1 summarizes the different factors that affect the prevalence of GI symptoms during exercising. By addressing factors such as exercise intensity, hydration, and dietary choices, healthcare providers and trainers can help athletes maintain their training and performance without compromising their GI health, ultimately enhancing athletic performance and long-term well-being.

**Variability of GI disorders based on exercise ** The prevalence and severity of GI symptoms among exercisers are highly variable, influenced by the type, duration, and intensity of physical activity. Each exercise modality imposes distinct mechanical, physiological, and environmental stressors on the GI system, resulting in different symptom profiles[11]. Endurance sports and activities such as running, cycling, triathlons, and swimming consistently report higher GI symptoms. Studies show that up to 70% of long-distance runners experience GI distress, with symptoms ranging from mild bloating and cramping to severe diarrhea and GI bleeding. The mechanical impact of running, combined with reduced splanchnic blood flow and increased intestinal permeability, contributes to both upper (nausea, reflux) and lower GI symptoms (cramping, diarrhea)[3]. Cyclists also experience a high prevalence of GI issues, particularly upper GI symptoms like heartburn and nausea, exacerbated by forward-leaning postures and prolonged exertion. Open-water swimmers are prone to nausea and vomiting, often due to swallowing air and water, exacerbated by waves and cold water[12].

HIIT involves alternating periods of intense anaerobic exertion with rest, leading to frequent GI symptoms during extreme sessions. The rapid shifts in intensity can temporarily redirect blood flow away from the GI tract to working muscles, impairing digestion and increasing the risk of nausea, cramping, and bloating[13]. However, compared to endurance sports, the shorter duration of HIIT generally reduces the risk of more severe complications like ischemic colitis. This pattern highlights the importance of gradual acclimatization and hydration strategies in minimizing symptoms[14].

Resistance training typically has a lower incidence of GI symptoms than endurance and high-intensity exercises. However, certain factors, such as improper breathing techniques, heavy lifting, or poor postural mechanics, can lead to abdominal discomfort, bloating, and even reflux[15]. High intra-abdominal pressure during intense lifting sessions can impair the LES’s function, predisposing athletes to acid reflux and related discomfort[16]. GI symptoms are often exacerbated by consuming large pre-workout meals or dietary supplements, particularly protein shakes, which have been linked to GI distress in some lifters. Swimming is generally associated with fewer GI symptoms due to the horizontal body position reducing gravitational impact on the intestines. However, competitive and open-water swimmers can experience nausea and upper GI discomfort, particularly in cold or choppy water conditions. Racquet sports, such as tennis and squash, present a moderate risk of GI issues due to intermittent high-intensity bursts, usually less severe than endurance sports. Dehydration and exertion in hot conditions can exacerbate nausea and cramping, particularly during prolonged matches[17].

CrossFit and triathlons combine endurance, resistance, and high-intensity elements, leading to a broad spectrum of GI symptoms. CrossFit participants may report bloating and reflux from rapid transitions between exercises. At the same time, triathletes often experience compounded symptoms across all stages, nausea from swimming, cramping from cycling, and diarrhea during the running phase[18]. The variability in GI symptoms across different exercise types underscores the necessity of sport-specific strategies to manage and prevent these issues. Endurance athletes may benefit from dietary modifications such as reducing fiber intake before events, while HIIT and weightlifters might focus on optimizing breathing techniques and avoiding heavy pre-exercise meals[19]. Recognizing these nuanced variations allows for more tailored interventions, enhancing performance while preserving athletes’ GI health.

**Differences in prevalence between elite athletes and recreational ** The prevalence of GI disorders differs significantly between elite athletes and recreational exercisers, primarily influenced by differences in training intensity, dietary practices, stress levels, and physiological demands. Elite athletes, particularly those involved in high-endurance sports, are more prone to GI symptoms than their recreational counterparts[20]. Studies have shown that 30% to 70% of elite endurance athletes report GI complaints during training or competition. This higher prevalence is attributed to the combined effects of prolonged exercise, increased physiological stress, dehydration, and greater reliance on high-energy, carbohydrate-rich diets, often consumed in large quantities during events[21]. These factors exacerbate GI symptoms, including nausea, vomiting, diarrhea, and abdominal pain. Additionally, reduced blood flow to the GI tract due to prolonged shunting towards working muscles during high-intensity exercise heightens their vulnerability to ischemic-related symptoms like cramping and GI bleeding[9].

In contrast, recreational exercisers tend to experience fewer and less severe GI symptoms, with reported prevalence ranging from 10% to 50% depending on the type and intensity of activity[3]. Recreational athletes are less likely to engage in prolonged high-intensity training, reducing the risk of exercise-induced intestinal permeability and other GI complications. However, poor hydration, inadequate warm-ups, or sudden increases in exercise intensity can still trigger symptoms, particularly in inexperienced individuals[22]. Common complaints include bloating, mild cramping, and reflux, often linked to dietary indiscretions or inadequate pre-exercise preparation. Elite athletes face additional psychological stressors from competitive pressures, which can exacerbate GI symptoms through mechanisms involving the gut-brain axis. Anxiety and stress can lead to increased GI motility or spasms, further worsening symptoms. In contrast, recreational exercisers may experience fewer psychological triggers, contributing to their lower prevalence of GI issues[23].

Nutritional practices also vary significantly between the two groups. Elite athletes often consume large volumes of sports drinks, gels, and supplements during training, which can overwhelm the GI system and lead to symptoms like diarrhea and cramping[24]. Recreational athletes are less likely to use these products intensively, reducing their risk of GI disturbances. Given these differences, tailored interventions are necessary. Elite athletes may benefit from individualized nutrition plans that optimize macronutrient timing and hydration strategies to minimize GI distress. Psychological support to manage stress and anxiety can also be beneficial[25]. For recreational exercisers, gradual increases in training intensity and education on proper hydration and dietary choices can help mitigate symptoms, enhancing their exercise experience without compromising GI health[26].

Pathophysiology of exercise-related GI disorders

Different pathophysiologic changes may occur in the GI tract due to exercise. These changes may include splanchnic hypoperfusion, increased intestinal permeability in exercise (“leaky gut”), impaired gut barrier function, changes in the microbial metabolites and short-chain fatty acids, changes in the gut-brain axis and neuroendocrine regulation, GI tract mechanical changes, and neurohormonal changes (Figure 2).

Reduced blood flow (splanchnic hypoperfusion): During intense physical activity, the body significantly redistributes blood flow to prioritize skeletal muscles, the heart, and the lungs, diverting it away from the GI tract. This physiological process, known as splanchnic hypoperfusion, is crucial for maintaining oxygen delivery to working muscles but can harm GI tissue integrity and function[27]. During moderate to high-intensity exercise, blood flow to skeletal muscles can increase up to 20-fold, facilitated by vasodilation in muscle capillaries. As a result, blood supply to non-essential organs, including the GI tract, decreases by 50%-80%, depending on the intensity and duration of the exercise. The sympathetic nervous system triggers vasoconstriction of splanchnic arteries to preserve blood pressure and direct resources to exercising muscles. This process is more pronounced in endurance and HIIT than low-impact exercises like walking or swimming[28].

Reduced blood supply leads to intestinal ischemia, compromising the oxygen and nutrient delivery to GI tissues. Prolonged ischemia can result in epithelial damage, increased mucosal permeability, and reduced motility, leading to symptoms such as abdominal cramping, diarrhea, and nausea[29]. Hypoperfusion can weaken tight junctions in the intestinal epithelium, increasing permeability or “leaky gut syndrome”. This allows bacteria, toxins, and antigens to translocate into the bloodstream, triggering systemic inflammation and GI distress[30]. Splanchnic hypoperfusion also impairs gastric motility, slowing gastric emptying and contributing to nausea, vomiting, and bloating. Athletes participating in prolonged endurance events frequently report these symptoms, especially under dehydrated or hyperthermic conditions. In severe cases, ischemia can cause mucosal erosion, leading to GI bleeding. This is commonly reported in endurance athletes, especially marathon runners, and can manifest as bloody diarrhea or hematochezia[9].

**Increased intestinal permeability in exercise (“leaky gut”) and impaired gut barrier ** Exercise-induced GI symptoms are often linked to increased intestinal permeability, commonly called “leaky gut”. This phenomenon disrupts the intestinal barrier, allowing larger molecules, toxins, and bacteria to pass from the gut lumen into the bloodstream, triggering systemic inflammation and various GI symptoms. Tight junctions, composed of proteins like occludin, claudins, and zonula occludens, play a crucial role in maintaining the intestinal epithelial barrier by regulating paracellular permeability. During prolonged or high-intensity exercise, tight junctions are disrupted due to reduced blood flow, leading to ischemia, impairing epithelial cell integrity, and damaging tight junction proteins[31]. Increased core body temperature during exercise can destabilize cellular structures and alter tight junction dynamics. Exercise-induced reactive oxygen species production exacerbates tight junction damage by promoting inflammatory pathways and direct oxidative injury to epithelial cells[32].

Disruption of tight junctions permits the translocation of lipopolysaccharides (LPS) from gram-negative bacteria into the bloodstream, leading to endotoxemia and systemic immune activation. This process is characterized by elevated levels of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin-6 (IL-6), contributing to GI symptoms like fatigue, cramping, and fever[33]. A recent human study by Roca Rubio et al[34] further supports these findings. In a cohort of endurance-trained athletes undergoing a 60-minute treadmill run at 80% of the maximum amount of oxygen, the authors observed significant increases in markers of intestinal permeability, immune activity, and oxidative stress. The lactulose/rhamnose ratio, a marker of small intestinal permeability, was negatively correlated with uric acid levels, suggesting a possible protective role of uric acid, and positively correlated with fecal chromogranin A, particularly in male participants. Though no direct association was found between permeability markers and GI symptoms in this controlled setting, perceived exertion strongly correlated with a combination of IL-6, IL-10, and salivary cortisol, pointing to a broader inflammatory response to exercise-induced barrier stress[34].

Increased intestinal permeability has been implicated in various GI symptoms, including abdominal cramping, bloating, nausea, and diarrhea. Endurance athletes often report these symptoms during prolonged events, especially under heat stress or dehydration. Persistent intestinal permeability and chronic inflammation may contribute to long-term health issues, including IBS-like symptoms and impaired recovery. This is particularly relevant for athletes with frequent high-intensity training without adequate recovery or nutritional support[35]. Understanding the role of tight junction disruption in exercise-related GI disorders highlights the importance of maintaining adequate fluid balance to prevent ischemic injury, supplementing with nutrients like glutamine, zinc, and polyphenols, which have been shown to enhance intestinal barrier integrity, and allowing sufficient time for epithelial repair and tight junction restoration between training sessions. These insights are critical for developing preventive strategies that minimize GI symptoms, improve athletic performance, and safeguard overall health[36].

**Exercise-induced microbial metabolites and short-chain fatty ** Physical activity, particularly of moderate intensity, has been shown to favorably alter the gut microbiota, increasing the relative abundance of butyrate-producing bacteria (e.g., Faecalibacterium prausnitzii, Roseburia spp.). Butyrate, a key short-chain fatty acid (SCFA), serves as a primary energy source for colonocytes, promotes the expression of tight junction proteins, and exerts anti-inflammatory effects by inhibiting nuclear factor-kappa B signaling pathways. These changes reinforce gut barrier function and may alleviate symptoms in inflammatory conditions such as IBD and IBS[37].

**Gut-brain axis and neuroendocrine ** The gut-brain axis represents a bidirectional communication network involving the enteric nervous system, autonomic nervous system (ANS), and hypothalamic-pituitary-adrenal (HPA) axis. Moderate exercise enhances vagal tone, promoting parasympathetic activity, which supports gut motility, secretion, and mucosal immunity. Additionally, exercise reduces cortisol levels, a stress hormone implicated in increased intestinal permeability and GI distress, thereby stabilizing gut physiology. Mind-body exercises like yoga and Tai Chi have been shown to reduce gut-brain axis dysfunction by attenuating HPA axis hyperactivity and modulating neurotransmitters like serotonin, which influence both mood and gut motility[38].

**Mechanical factors and their role in GI ** Exercise-related GI symptoms can also be attributed to the mechanical forces exerted on the abdominal organs during physical activity. This is particularly pronounced in high-impact sports such as running, tennis, or aerobic activities, where repetitive jostling can lead to discomfort and various GI symptoms[39]. The repetitive up-and-down movement of the body during specific exercises causes increased intra-abdominal pressure, which can compress the stomach and intestines, leading to symptoms such as nausea, acid reflux, and cramping and aggravating GERD by forcing gastric contents into the esophagus[16]. The mechanical disturbance may delay gastric emptying, particularly in prolonged or high-intensity movement activities, contributing to bloating and upper GI discomfort. Repeated mechanical stress may cause microtrauma to the intestinal mucosa, increasing intestinal permeability and exacerbating symptoms such as abdominal pain and diarrhea. Some sports may induce specific effects. For example, running is known for causing “runner’s trots” due to high-impact jostling and increased intestinal motility. Though cycling has a lower mechanical impact than running, sustained forward flexion can still cause compression-related GI issues, such as nausea and reflux. Heavy lifting may increase intra-abdominal pressure, heightening the risk of transient GI discomfort, especially in athletes with pre-existing GI conditions[40].

**Neurohormonal ** Exercise induces a complex interplay between neurohormonal responses and GI function. Neurohormonal changes involve activating the ANS and releasing stress-related hormones, which collectively influence GI motility, secretion, and barrier function[41]. During physical activity, the body responds by releasing stress hormones such as cortisol, adrenaline (epinephrine), and noradrenaline (norepinephrine). These hormones are part of the HPA axis and the sympathetic nervous system’s “fight or flight” response, which affects GI function in different ways. High levels of adrenaline and noradrenaline divert energy away from non-essential functions like digestion, slowing gastric emptying and intestinal peristalsis. This can lead to symptoms such as nausea, bloating, and constipation during or after exercise[42]. Elevated cortisol levels have been associated with disrupting tight junction proteins in the gut lining, exacerbating “leaky gut”, and increasing the risk of systemic inflammation and GI distress[43].

The ANS, comprising the sympathetic and parasympathetic branches, is critical in regulating GI activity during exercise. During high-intensity or prolonged exercise, sympathetic activation inhibits digestive processes, leading to decreased salivary secretion, reduced digestive enzyme production, and impaired gut motility[44]. Suppressing parasympathetic activity (responsible for “rest and digest” functions) further diminishes GI motility, increasing the likelihood of GI symptoms such as cramping and bloating. High-intensity exercise is associated with a stronger neurohormonal response, leading to more pronounced GI symptoms such as vomiting, diarrhea, and abdominal pain. Moderate-intensity exercise tends to have a milder neurohormonal impact, often resulting in fewer GI disturbances than high-intensity regimens[45].

Risk factors for developing GI symptoms during exercise

**Exercise-related ** Exercise-related factors significantly influence the development and severity of GI symptoms during physical activity, such as exercise intensity and duration, type of exercise, environmental conditions, hydration status, and electrolyte imbalance[46]. High-intensity exercise, such as sprinting, HIIT, and endurance events, is strongly associated with GI distress due to increased sympathetic nervous system activation, reduced splanchnic blood flow, delayed gastric emptying, and heightened intestinal permeability[47]. Symptoms like nausea, vomiting, and abdominal cramping are frequently reported in these scenarios. Prolonged exercise, particularly activities lasting over two hours, such as marathons and triathlons, exacerbates GI symptoms due to the cumulative effects of dehydration, energy depletion, and ischemic conditions, increasing the risk of severe issues like diarrhea and GI bleeding. The type of exercise also plays a crucial role. High-impact activities such as running and tennis are associated with lower GI symptoms, including diarrhea and cramping, due to the mechanical jostling of abdominal organs[3]. Conversely, low-impact activities like swimming and cycling tend to cause upper GI symptoms, such as nausea and reflux, influenced by body positioning and reduced mechanical stress. Resistance training, especially heavy lifting, can exacerbate reflux and bloating due to increased intra-abdominal pressure, particularly when improper breathing techniques or lifting postures are employed[48].

Environmental conditions further contribute to GI symptom prevalence. Heat and humidity exacerbate dehydration and hyperthermia, impairing blood flow to the GI tract and increasing the likelihood of nausea, vomiting, and diarrhea[35]. High-altitude training also poses a risk due to reduced oxygen availability, which can worsen intestinal ischemia and delay gastric emptying, leading to hypoxia-related GI issues like nausea and cramping[49]. Hydration status and electrolyte balance are critical factors. Dehydration reduces plasma volume, intensifying splanchnic hypoperfusion and impairing digestive processes, resulting in constipation, cramping, and nausea. Electrolyte imbalances, particularly sodium and potassium, can further disrupt GI motility, leading to bloating, cramps, and diarrhea, especially in prolonged endurance events. Proper hydration and electrolyte replenishment are essential to maintaining GI function during extended physical activity[50].

**Dietary ** Dietary factors, such as pre-exercise meals, inadequate hydration, or electrolyte imbalance, play a significant role in developing GI symptoms during exercise, particularly concerning the composition and timing of pre-exercise meals[3]. Consuming high-fat or high-fiber foods before physical activity can slow gastric emptying and increase the risk of GI distress. High-fat meals require more time for digestion, leading to delayed gastric emptying and symptoms such as bloating, nausea, and abdominal discomfort[2]. Similarly, high-fiber foods can increase bulk and gas production in the intestines, contributing to cramping and diarrhea, particularly during high-impact or endurance exercises. Consuming large meals close to the start of exercise further exacerbates these issues, as undigested food remains in the stomach, heightening the risk of reflux and nausea[51]. Inadequate hydration and electrolyte imbalances also contribute to exercise-induced GI symptoms. Dehydration reduces blood volume, exacerbating splanchnic hypoperfusion and impairing digestive processes, leading to constipation, cramping, and nausea[52]. During prolonged or intense exercise, the loss of electrolytes, particularly sodium and potassium, can disrupt GI motility and increase the likelihood of bloating, diarrhea, and abdominal pain. Sodium depletion, often associated with excessive fluid intake without adequate electrolyte replacement, can lead to hyponatremia, exacerbating GI symptoms and posing serious health risks[53].

**Individual ** Individual factors, including pre-existing GI disorders, genetic predisposition, and gut microbiota composition, significantly influence the likelihood of developing GI symptoms during exercise[54]. Athletes with pre-existing GI conditions, such as IBS, IBD, or GERD are more susceptible to exercise-induced GI distress[55]. For instance, IBS patients often experience heightened visceral sensitivity and altered intestinal motility, which can be exacerbated by physical activity, leading to symptoms such as cramping, diarrhea, and bloating[36]. Similarly, those with GERD are more prone to reflux and heartburn during high-intensity or high-impact exercises due to increased intra-abdominal pressure and mechanical jostling of the stomach. Genetic predisposition also plays a role in determining an individual’s susceptibility to GI symptoms during exercise. Variations in genes associated with inflammatory pathways, mucosal integrity, and neurotransmitter regulation can influence GI tract responses under physical stress[56]. Additionally, individuals with a family history of GI disorders may inherit a heightened risk of developing similar symptoms, particularly when subjected to prolonged or intense physical activity. The composition of the gut microbiota is another crucial factor. A diverse and balanced microbiota supports GI health by maintaining the intestinal barrier and modulating immune responses. However, dysbiosis, an imbalance in gut microbial populations, can impair these protective mechanisms, increasing intestinal permeability and promoting systemic inflammation during exercise[57,58]. This can lead to symptoms such as nausea, diarrhea, and abdominal pain, particularly in endurance athletes.

Impact of exercise on GI health

**Acute ** The acute effects of exercise on GI health often manifest as temporary symptoms that occur during or immediately after physical activity, particularly in moderate to high-intensity exercise. Despite being transient, these symptoms can significantly impair performance, comfort, and recovery. During exercise, splanchnic hypoperfusion, a reduction in blood flow to the GI tract, occurs as the body prioritizes blood supply to working muscles, heart, and lungs. This ischemic response, increased core body temperature, and mechanical stress disrupt normal GI function[27]. Common acute symptoms include nausea, bloating, abdominal cramps, diarrhea, and vomiting. Endurance sports like marathons and triathlons are particularly associated with these effects due to the prolonged nature of the exercise and cumulative physiological stress[2]. For example, “runner’s trots” is a well-documented phenomenon characterized by the urge to defecate during prolonged running, likely due to increased intestinal motility and mechanical jostling[3].

Additionally, high-intensity exercise can slow gastric emptying, accumulate gastric contents, and contribute to symptoms such as reflux, nausea, and fullness. Dehydration further exacerbates these effects, impairing digestion and increasing the likelihood of cramping and GI discomfort[59]. In some cases, intestinal permeability increases (“leaky gut”), allowing endotoxins and bacteria to translocate into the bloodstream, triggering an inflammatory response and systemic symptoms like fatigue or fever, and in rare cases, sepsis-like symptoms[60]. While these temporary symptoms often resolve shortly after exercise, they can significantly impact an athlete’s performance and training consistency. Proper hydration, adequate fueling strategies, and avoiding high-fat or high-fiber meals close to exercise can help mitigate acute GI symptoms[61]. Understanding the factors contributing to these short-term effects is essential to minimize their occurrence and support athletes in achieving their performance goals.

**Chronic ** The chronic effects of long-term exercise on GI health can be protective and detrimental, depending on the intensity, duration, and frequency of the physical activity. Regular moderate-intensity exercise positively affects GI function, while excessive or high-intensity training, particularly in endurance athletes, can lead to chronic GI dysfunction and damage[62]. Moderate, consistent exercise is widely recognized for its beneficial impact on GI health. It enhances gut motility, reducing constipation risk by promoting regular bowel movements and improving colonic transit time. This effect is particularly valuable in sedentary individuals or those with conditions such as IBS, where slow motility often exacerbates symptoms. Additionally, long-term exercise positively influences the gut microbiota, fostering microbial diversity and increasing the abundance of beneficial bacterial species, such as Bifidobacterium and Faecalibacterium. A more diverse and balanced gut microbiome strengthens the intestinal barrier, reduces systemic inflammation, and promotes overall gut health[63].

Moreover, regular physical activity has been linked to a reduced risk of chronic GI diseases, including colorectal cancer and diverticular disease. Improved intestinal motility and reduced fecal transit time decrease exposure to carcinogenic substances in the colon, while the anti-inflammatory effects of exercise contribute to a healthier GI environment[64]. Furthermore, exercise supports systemic metabolic health, reducing obesity and insulin resistance, both of which are associated with increased GI disease risk[65].

While moderate exercise is protective, excessive or high-intensity long-term exercise, particularly in endurance sports, can adversely affect GI function. One of the most significant mechanisms is chronic splanchnic hypoperfusion. Repeated reductions in blood flow to the gut during prolonged training or competition can cause cumulative ischemic damage, impairing mucosal integrity and increasing intestinal permeability[27]. Over time, this results in a “leaky gut”, allowing bacterial toxins such as LPS to enter the bloodstream, triggering chronic inflammation and systemic symptoms[66]. Endurance athletes are particularly prone to chronic GI symptoms, including persistent diarrhea, abdominal pain, bloating, and in severe cases, GI bleeding. Repeated ischemic stress combined with mechanical jostling of the gut can result in mucosal injury, stress-related gastritis, and minor intestinal bleeding, often manifesting as iron deficiency anaemia[3,8]. Prolonged dysregulation of gut function can also contribute to malabsorption and nutritional deficiencies, which impair performance and recovery in athletes. Chronic overtraining and inadequate caloric intake can also disrupt the gut microbiota (dysbiosis), further weakening the intestinal barrier and perpetuating inflammation[67]. This imbalance has been linked to GI symptoms like those seen in FGIDs, such as IBS, in athletes engaged in long-term intensive training regimens[68].

**Effects on gut ** Exercise has a notable impact on gut microbiota diversity and composition, with outcomes largely dependent on the intensity, duration, and frequency of physical activity[69]. Moderate-intensity exercise has been associated with a more diverse and balanced gut microbiota, which is a key indicator of GI health. Studies have reported increased levels of beneficial bacteria such as Bifidobacterium, Faecalibacterium prausnitzii, and Akkermansia muciniphila in physically active individuals[70]. These microbes contribute to gut barrier integrity, inflammation regulation, and metabolic efficiency by producing SCFAs, particularly butyrate, which supports colonocyte health and enhances mucosal immunity[71].

The mechanisms behind these changes include improved gut motility, accelerated transit time, and favorable alterations in the gut environment (e.g., pH and oxygen levels), which promote the growth of anaerobic, anti-inflammatory species[1]. Additionally, exercise modulates immune responses by increasing anti-inflammatory cytokines and immunoglobulin A, further promoting microbial balance[6]. However, the effects of exercise on the microbiota are dose-dependent. While moderate activity supports microbial health, excessive or high-intensity training, common among endurance athletes, has been associated with dysbiosis, characterized by reduced microbial diversity and increased gut permeability[72]. This can lead to the translocation of bacterial endotoxins like LPS, triggering systemic inflammation and GI symptoms such as cramping, bloating, and diarrhea[37]. In the long term, this may impair nutrient absorption and recovery, thereby affecting performance and overall health[73].

Importantly, the relationship between exercise and gut microbiota is bidirectional. A well-balanced microbiota may enhance exercise performance by supporting immunity, reducing inflammation, and providing energy through SCFA metabolism[69]. To optimize this interplay, individuals are advised to maintain a moderate and consistent training regimen, incorporate prebiotic and probiotic foods, ensure adequate hydration, and allow sufficient recovery time[74].

Clinical implications and consequences of exercise-induced GI manifestations

Exercise-induced GI manifestations can have significant clinical implications, particularly for athletes, as they impact both performance and overall health. These symptoms, ranging from mild discomfort to severe complications, are influenced by exercise intensity, duration, hydration status, and individual susceptibility[3]. GI symptoms during exercise can severely impair athletic performance by reducing endurance, limiting participation, and in some cases, leading to withdrawal from competitions[2]. Symptoms such as nausea, bloating, abdominal cramping, vomiting, and diarrhea can cause significant discomfort and disrupt an athlete’s focus and energy expenditure. GI distress is particularly detrimental for endurance athletes, such as marathon runners, triathletes, and cyclists[75]. Studies report that up to 30%-70% of endurance athletes experience GI symptoms during prolonged events, with lower GI complaints such as diarrhea and cramping being more common in runners due to mechanical stress and altered motility[3]. These symptoms interfere with pace and endurance and can lead to forced rest or withdrawal from events, compromising competitive outcomes.

In sports requiring high-intensity effort, such as HIIT or competitive weightlifting, symptoms like reflux, vomiting, or bloating can result from increased intra-abdominal pressure or delayed gastric emptying. These manifestations impair the athlete’s ability to exert maximum effort, limiting performance potential. Moreover, chronic GI distress can lead to reduced nutrient absorption and energy availability, further diminishing stamina, recovery, and muscle repair, creating a vicious cycle of underperformance[76]. Psychological stress exacerbates these consequences, as athletes under competitive pressure may experience heightened GI symptoms through gut-brain axis interactions. The combination of physical and psychological strain can lead to anxiety surrounding performance, further worsening GI distress and its impact on competition outcomes[77].

While many exercise-induced GI symptoms are mild and transient, severe cases can result in significant medical complications, particularly in endurance sports. One major complication is ischemic colitis, which occurs due to prolonged splanchnic hypoperfusion. During prolonged or intense exercise, blood flow is diverted away from the GI tract to support working muscles, heart, and lungs[14]. This ischemic state can damage the intestinal mucosa, resulting in inflammation, ulceration, and in some cases, bleeding. Ischemic colitis is often seen in endurance athletes participating in marathons, triathlons, or ultra-endurance events. It presents with symptoms such as severe abdominal pain, bloody diarrhea, and systemic fatigue. Prompt medical attention is required to prevent long-term complications such as bowel necrosis or perforation[78]. Another serious concern is rectal bleeding, which can result from repetitive mechanical stress and mucosal damage, particularly in runners. Known as “runner’s hematuria” or exercise-induced GI bleeding, this condition is exacerbated by dehydration, NSAID use, and prolonged ischemia[9]. While the bleeding is often mild and self-limiting, chronic or severe cases can lead to iron deficiency anemia, fatigue, and compromised athletic performance[79].

Endurance athletes are also at risk of small intestinal injury and increased intestinal permeability (“leaky gut”), which can allow endotoxins like LPS to enter the bloodstream. This condition, known as exercise-induced endotoxemia, triggers systemic inflammation, fever, and fatigue, further impairing recovery and performance[80]. In rare cases, excessive endotoxemia can lead to sepsis-like symptoms, posing significant health risks if untreated. The clinical implications of exercise-induced GI manifestations are far-reaching, with significant consequences for athletic performance and health. For athletes, symptoms such as nausea, vomiting, cramping, and diarrhea impair endurance, disrupt competitive outcomes, and undermine long-term training goals[81]. Severe complications, including ischemic colitis, rectal bleeding, and endotoxemia, not only jeopardize performance but also carry significant medical risks that require prompt diagnosis and management[82].

Effects of exercise on special populations

**GI considerations in female ** GI symptoms during exercise are particularly relevant in female athletes due to the unique physiological and hormonal factors distinguishing them from their male counterparts[83]. Female athletes often report a higher prevalence and severity of GI symptoms, influenced by the interplay between exercise, the menstrual cycle, and sex hormones such as estrogen and progesterone. These factors can exacerbate GI distress, impact athletic performance, and require tailored management strategies[84].

The menstrual cycle introduces hormonal fluctuations that significantly influence GI motility, sensitivity, and barrier integrity, particularly during exercise. In the luteal phase, progesterone levels are elevated, which can slow gastric emptying and intestinal motility. This delayed transit time often contributes to bloating, constipation, and abdominal discomfort. When combined with physical exertion, these symptoms can become more pronounced, impairing performance in endurance and high-intensity sports[84]. Elevated estrogen levels during the menstrual cycle can increase GI sensitivity and contribute to nausea and cramping, particularly during prolonged or intense exercise. Estrogen also modulates gut permeability, which may exacerbate symptoms like diarrhea and “leaky gut” during strenuous activity[74].

Female athletes report GI symptoms more frequently than males, with studies indicating a higher incidence of nausea, bloating, cramping, and diarrhea during exercise. This may be due to a combination of hormonal influence, visceral sensitivity, and dietary practices[18]. The menstrual cycle’s impact on motility and gut sensitivity increases susceptibility to symptoms at different phases. Female athletes are often more sensitive to visceral pain, making them more prone to discomfort from gut ischemia, mechanical jostling, and delayed gastric emptying during exercise[84]. Many female athletes adopt specific dietary patterns, such as low energy availability or restrictive eating, which can disrupt gut function and worsen GI symptoms[85]. Conditions such as the female athlete triad, characterized by energy deficiency, menstrual irregularities, and low bone density, can further exacerbate GI issues due to impaired nutrient absorption and gut motility[86].

Hormonal contraceptives, commonly used by female athletes to regulate menstrual cycles, can also affect GI function. Oral contraceptives alter estrogen and progesterone levels, influencing gut motility and barrier function. Some athletes experience reduced GI symptoms with contraceptive use, while others report worsening symptoms, such as nausea and bloating, highlighting the need for individualized management strategies[87].

Female athletes can benefit from targeted strategies to minimize GI distress and optimize performance. Understanding symptom patterns across the menstrual cycle can help plan training and competition schedules. For example, endurance events may be better tolerated during the follicular phase when GI motility is less impaired[88]. Female athletes should avoid high-fat, high-fiber, and large pre-exercise meals during phases of increased GI sensitivity. Adequate hydration and electrolyte replenishment are crucial, especially during the luteal phase when fluid retention can exacerbate symptoms. Gradual adaptation to specific foods and hydration regimens during training can reduce GI symptoms on competition days. For athletes using hormonal contraceptives, monitoring GI responses and adjusting formulations as needed can help mitigate adverse effects[89].

**Effects of exercise on older adults and their unique GI challenges with ** Exercise provides numerous health benefits for older adults, including improved cardiovascular function, muscle strength, and enhanced quality of life. However, due to age-related physiological changes, comorbidities, and altered gut function, older individuals face unique GI challenges during exercise[90]. These factors can influence how older adults respond to physical activity and predispose them to exercise-induced GI symptoms.

As individuals age, the GI system undergoes several functional and structural changes. One notable change is the slowing of gastric emptying and intestinal motility, which can lead to symptoms such as bloating, constipation, and abdominal discomfort[91]. Physical activity, while beneficial for promoting gut motility and alleviating constipation, can sometimes exacerbate GI symptoms, mainly if vigorous exercise is performed after large meals. In addition, older adults often experience a natural decline in splanchnic blood flow, and this reduction is magnified during exercise as blood is redistributed to working muscles. This diminished perfusion can lead to ischemic changes in the gut, resulting in abdominal cramping, nausea, or even mild GI bleeding during prolonged or high-intensity activities[27].

Furthermore, older adults frequently have comorbid conditions such as GERD, diverticular disease, or IBS, which can make them more susceptible to GI symptoms during exercise[90]. For example, GERD is common in older populations due to a weakening of the LES, and exercise, particularly activities that increase intra-abdominal pressure, such as resistance training or heavy lifting, can exacerbate reflux symptoms like heartburn or regurgitation. Similarly, diverticular disease, characterized by small outpouchings in the colon, may cause discomfort during activities that involve repetitive abdominal jostling, such as running or high-impact aerobics[92].

Hydration also presents a unique challenge for older adults during exercise. The aging process reduces thirst sensation and kidney function, increasing the risk of dehydration[93]. Dehydration, coupled with electrolyte imbalances, can exacerbate GI symptoms like constipation, cramping, and nausea. Ensuring adequate hydration before, during, and after exercise is particularly important in this population to maintain GI health and prevent related complications. Despite these challenges, moderate exercise remains a valuable intervention for improving GI health in older adults. Activities like walking, swimming, and yoga can enhance gut motility, reduce constipation, and support overall digestive function without imposing significant stress on the GI system[94]. Additionally, low-impact aerobic exercises promote circulation to the splanchnic region, improving nutrient absorption and reducing the risk of ischemic events[95].

Exercises in specific GI diseases

GERD: GERD is a chronic condition where stomach acid or, occasionally, bile irritates the lining of the esophagus, causing symptoms such as heartburn, regurgitation, chest pain, and difficulty swallowing. While exercise generally benefits overall health, its relationship with GERD is complex. Physical activity can both trigger and alleviate symptoms, depending on the type, intensity, and timing of exercise. Understanding how exercise impacts GERD is crucial for managing symptoms and improving the quality of life for individuals with this condition[96].

Certain types of exercise, particularly high-impact or vigorous activities, can trigger GERD symptoms in some individuals. This is often due to the increased intra-abdominal pressure and body movements that occur during activities like running, weightlifting, or HIIT. When intra-abdominal pressure rises, it can cause LES, a valve that prevents stomach contents from flowing back into the esophagus to relax. This relaxation allows stomach acid to reflux into the esophagus, causing heartburn, regurgitation, and discomfort. Exercises that involve bending over or lying flat, such as certain yoga poses or core exercises, can also exacerbate GERD symptoms by increasing the likelihood of acid reflux[97].

Additionally, exercising on a full stomach can increase the likelihood of GERD symptoms, as the stomach is already distended, and the LES is more prone to opening in response to physical activity[98]. Similarly, vigorous exercise in a hot environment can exacerbate symptoms by increasing stomach acid production and promoting dehydration, which can worsen acid reflux. On the other hand, moderate-intensity exercise can have beneficial effects on GERD. Regular physical activity, such as walking, swimming, or cycling, can help with weight management, which is crucial for individuals with GERD[99]. Obesity, particularly abdominal obesity, increases intra-abdominal pressure and can exacerbate reflux by pushing stomach contents upward into the esophagus. By maintaining a healthy weight, moderate exercise reduces this pressure and helps prevent GERD symptoms[100].

Exercise also improves overall digestive health and gut motility, reducing symptoms like bloating and indigestion, often associated with GERD. Low-impact exercises, such as yoga and Tai Chi, have been found to alleviate stress, which is a common trigger for GERD flare-ups. These exercises help regulate the ANS, reduce anxiety, and improve breathing, all of which can reduce GERD symptoms[101]. Additionally, exercises that focus on strengthening the core and abdominal muscles may improve posture and support the digestive organs, potentially reducing reflux episodes[102].

For individuals with GERD, it is important to choose the right type of exercise and take steps to minimize the risk of triggering symptoms. Moderate-intensity aerobic exercises, such as walking, cycling, or swimming, are preferable to high-impact or intense activities, as they help reduce intra-abdominal pressure and support weight management. It is also advisable to avoid high-impact exercises or activities that involve bending over or lying flat immediately after meals, as these positions can increase the likelihood of acid reflux. Exercising on an empty stomach or at least 2-3 hours after eating helps prevent reflux caused by a distended stomach[103]. Wearing comfortable, loose-fitting clothing that does not place additional pressure on the abdomen is essential. While staying hydrated is important, large amounts of fluids should be avoided immediately before or during exercise to prevent increased stomach volume, which can promote reflux[104]. For those with more severe GERD symptoms, working with a healthcare provider to develop a tailored exercise plan that accommodates individual needs and limitations is crucial[99]. Table 2 describes some studies of the effect of exercise on patients with GERD.

**Peptic ** Peptic ulcers are open sores that develop on the inner lining of the stomach, small intestine, or esophagus, often caused by an imbalance between stomach acid and the protective mechanisms of the GI tract. The primary causes of peptic ulcers include infection with Helicobacter pylori bacteria and the prolonged use of NSAIDs[105]. Symptoms of peptic ulcers include abdominal pain, bloating, nausea, and indigestion. While treatment typically involves medication to reduce stomach acid and antibiotics for Helicobacter pylori infection, exercise can play a supportive role in managing symptoms, improving recovery, and preventing recurrence[106]. Regular physical activity can benefit individuals with peptic ulcers in several ways. First, exercise can reduce stress, which is a known trigger for ulcer formation and symptom exacerbation. The physiological and psychological benefits of exercise, including the release of endorphins and improved mood, help alleviate stress, which can lower the frequency of flare-ups. Additionally, moderate-intensity aerobic exercise such as walking, cycling, or swimming can improve circulation, promoting better oxygenation and healing of the GI mucosa[107]. Exercise also helps with weight management. Being overweight or obese increases the risk of developing ulcers, especially due to the increased pressure on the stomach and the possible association with conditions like GERD. Regular exercise helps maintain a healthy weight, reducing pressure and preventing additional strain on the stomach lining[96].

While exercise has many benefits for individuals with peptic ulcers, some precautions should be taken to avoid exacerbating symptoms. High-intensity exercises or activities that increase abdominal pressure, such as weightlifting or vigorous core exercises, may irritate the stomach lining and worsen symptoms like pain or nausea[2]. Engaging in moderate-intensity activities such as walking or cycling is recommended, as these are less likely to cause discomfort or strain on the abdomen[108]. Exercise timing is also essential. Avoiding exercise immediately after eating is best, as physical activity on a full stomach may increase stomach acid production and discomfort[109]. Additionally, individuals with peptic ulcers should avoid exercising in hot or dehydrated conditions, as dehydration can worsen symptoms[108]. Staying hydrated during exercise is also advisable, but drinking too much water too quickly can lead to bloating or discomfort[110]. A well-balanced diet alongside exercise can also promote healing, as certain foods, such as spicy or acidic foods, can irritate the ulcer, while fiber-rich foods and lean proteins support overall digestive health[108].

For individuals with peptic ulcers, the best approach to exercise is to start slowly with low-impact activities that are gentle on the stomach. Walking or swimming are excellent choices, as they promote circulation, reduce stress, and support overall health without causing strain on the abdomen[111]. Moderate-intensity exercises can be gradually incorporated as symptoms improve, but it’s essential to listen to the body and adjust the routine based on how the stomach feels. Avoiding high-intensity workouts, heavy lifting, and exercises that place undue pressure on the abdomen (such as certain yoga poses) is advisable, especially if ulcer symptoms are active[112]. For those who experience chronic stress, mind-body exercises like yoga or Tai Chi, which focus on relaxation and breathing techniques, can further help reduce stress and improve overall digestive health. These exercises promote physical well-being and provide psychological benefits, contributing to symptom management[113].

**Cancer in the GI ** Exercise has been widely studied for its beneficial effects on various aspects of health, including its role in cancer prevention and management. Specifically, research has shown that regular physical activity can have a positive impact on cancers of the GI tract, such as colorectal, esophageal, gastric, and pancreatic cancer. These benefits are attributed to the physiological and metabolic changes exercise induces in the body, which can help prevent cancer initiation, progression, and recurrence[114].

Exercise has been shown to reduce the risk of colorectal cancer, one of the most common types of GI cancer. The protective mechanisms behind this include improvements in gut motility, reduced inflammation, and gut microbiome modulation[115]. Regular physical activity enhances bowel movements, decreasing the time potential carcinogens stay in contact with the intestinal lining. This reduction in transit time lowers the risk of developing colorectal cancer by decreasing the exposure of colonic mucosa to harmful substances[116]. Moreover, exercise helps regulate body weight and prevent obesity, which is a known risk factor for several types of cancer, including colorectal cancer[117]. Exercise also reduces circulating insulin and insulin-like growth factors, both of which are implicated in cancer cell growth and proliferation. Regular physical activity improves immune function, reduces systemic inflammation, and enhances antioxidant defenses, all contributing to a lower cancer risk[118].

Exercise also plays a critical role in the management of cancer, particularly for individuals undergoing chemotherapy or radiation therapy for GI cancers. These treatments often cause side effects like fatigue, nausea, loss of appetite, and GI discomfort, which can severely affect the quality of life. Regular physical activity has been shown to reduce treatment-related fatigue and improve physical function, mental health, and overall quality of life[119]. In colorectal cancer survivors, exercise has been shown to reduce the risk of cancer recurrence and improve long-term survival rates. Studies indicate that individuals who engage in regular physical activity after completing cancer treatment have a significantly lower risk of developing secondary cancers and experiencing cancer recurrence[120]. The exact mechanisms behind this benefit include improved immune surveillance, reduced systemic inflammation, and enhanced endothelial function, all of which help prevent the growth of cancer cells[120].

For survivors of GI tract cancers, particularly colorectal cancer, exercise is an important factor in reducing the risk of recurrence. Research suggests that moderate-intensity aerobic exercise (such as walking, cycling, or swimming) combined with resistance training can help improve survival outcomes[121]. Exercise helps by decreasing levels of circulating inflammatory markers, improving metabolic health, and enhancing immune system function, which collectively play a role in minimizing the chance of cancer regrowth[122]. Additionally, exercise influences the gut microbiome, an area of growing interest in cancer prevention. A healthy, diverse gut microbiota has been linked to better immune function and reduced inflammation, both of which can influence cancer outcomes. Exercise-induced changes in the gut microbiome may help support the body’s ability to fight cancer cells and reduce the risk of recurrence[123]. However, further research is needed to understand this relationship fully.

The American Cancer Society and other health organizations recommend 150 minutes of moderate-intensity aerobic exercise per week combined with muscle-strengthening activities on two or more days a week for cancer prevention and survivorship[124]. For individuals with a history of GI cancers, exercise programs should be tailored to the individual’s treatment stage and physical capacity. Start with low-impact exercises and gradually increase intensity to avoid overexertion, especially in those undergoing or recently completed cancer treatment[125]. Exercise programs for cancer survivors should focus on improving strength, flexibility, cardiovascular fitness, and mental well-being. Additionally, incorporating stretching, breathing exercises, and relaxation techniques can help alleviate anxiety and improve overall physical and psychological health during cancer recovery[126]. Table 3 summarizes some studies concerning physical activity’s relation to the risk and outcome of GI cancer.

**Exercise and gallbladder ** Gallbladder diseases, including gallstones and cholecystitis, are common conditions that can significantly impact digestive health and quality of life. The gallbladder plays a crucial role in digestion by storing bile, which helps break down fats in the intestines. Disruptions in its function, such as the formation of gallstones or inflammation, can cause pain and indigestion, in severe cases, require surgical intervention (cholecystectomy)[127]. Research suggests that regular physical activity can have both preventive and therapeutic effects on gallbladder health by influencing bile production, cholesterol metabolism, and body weight, all of which are factors associated with gallbladder diseases (Table 4)[128].

One of the most important factors in the development of gallstones is obesity, as excess body fat, particularly abdominal fat, increases the concentration of cholesterol in bile, which can lead to the formation of gallstones. Studies have shown that regular physical activity helps maintain a healthy weight, reduce abdominal fat, and improve cholesterol metabolism, reducing the risk of gallstone formation[129]. Aerobic exercises, such as walking, cycling, and swimming, have been particularly effective in reducing visceral fat, which is closely linked to the development of gallstones[130].

Additionally, exercise can improve lipid profiles, increasing the levels of high-density lipoprotein (HDL) cholesterol. HDL cholesterol is known to help prevent gallstone formation by reducing the cholesterol saturation in bile[131]. A healthy balance of HDL cholesterol promotes the solubility of bile, thus preventing the crystallization of cholesterol that forms gallstones. Moreover, regular physical activity enhances gallbladder motility, encouraging the emptying of bile from the gallbladder. Poor gallbladder emptying, or hypomotility, is another risk factor for gallstone formation, as it leads to bile stagnation and cholesterol buildup[132]. Exercise helps stimulate the gallbladder to contract and empty more regularly, reducing the risk of bile sludge and gallstones[128].

For individuals diagnosed with gallbladder disease, particularly those who have undergone cholecystectomy, regular exercise can aid in the recovery process and improve overall digestive function[133]. After gallbladder removal, bile is no longer stored and concentrated, which can lead to digestive disturbances, including difficulty digesting fatty foods. Exercise has been shown to help improve digestion and nutrient absorption in individuals without a gallbladder by promoting more efficient bile flow directly from the liver to the small intestine[130]. In the case of cholecystitis or symptomatic gallstones, exercise may help reduce the severity of symptoms such as bloating, abdominal pain, and indigestion, particularly when combined with dietary changes[128]. However, it is important to avoid high-intensity or strenuous exercise during active inflammation or during an acute gallbladder attack. In these cases, exercise should be resumed gradually and under the guidance of a healthcare provider to avoid exacerbating symptoms[128]. In addition to weight management, exercise can help manage other lifestyle factors associated with gallbladder diseases, such as dietary habits and insulin sensitivity[134]. Dietary interventions, such as reducing intake of high-fat and high-cholesterol foods, can be complemented by regular exercise to improve overall health and reduce the risk of gallstone formation or gallbladder dysfunction. For individuals with insulin resistance or metabolic syndrome, regular exercise helps improve insulin sensitivity and reduce the risk of gallstones by promoting a healthy metabolic state and reducing fat accumulation around the liver and gallbladder[135].

IBS: IBS is a common FGID characterized by abdominal pain, bloating, and changes in bowel habits, including diarrhea, constipation, or alternating between the two[136]. Although the exact cause of IBS is unknown, it is believed to involve a combination of factors such as intestinal motility dysfunction, gut sensitivity, and altered gut microbiota. IBS is often triggered or exacerbated by stress, diet, and physical activity, which makes the relationship between exercise and IBS particularly important[137]. While some people with IBS may experience GI symptoms worsened by exercise, others find that regular physical activity can help reduce symptoms and improve overall well-being[138].

In many individuals with IBS, regular exercise has been shown to help alleviate symptoms and improve both gut motility and mental well-being. Aerobic exercise, such as walking, jogging, cycling, and swimming, helps improve bowel function by promoting regular intestinal motility[36]. This can be particularly beneficial for those with IBS and constipation, as exercise encourages more frequent bowel movements and helps prevent the bloating and discomfort associated with slow digestion[139]. For individuals with IBS-diarrhea, moderate-intensity exercise can help regulate gut function and reduce the frequency and urgency of bowel movements[140]. Exercise has a calming effect on the gut-brain axis, reducing stress and the visceral hypersensitivity often seen in IBS patients. By improving the body’s ability to respond to stress and reducing gut sensitivity, exercise can help alleviate the abdominal pain and bloating associated with IBS[36].

Psychological stress is a significant trigger for IBS symptoms, and exercise is a powerful tool for stress reduction. Regular physical activity has been shown to increase the production of endorphins and other neurotransmitters, which help to reduce feelings of anxiety and depression, commonly seen in individuals with IBS[141]. Yoga and Tai Chi combine physical activity with deep breathing and relaxation, making them especially beneficial for IBS patients. These exercises reduce stress and promote mind-body awareness, which can help individuals with IBS manage symptoms more effectively[142]. Emerging research suggests that exercise may influence the gut microbiota, the diverse community of bacteria, and other microorganisms that play a crucial role in digestion and overall health. Dysbiosis, or an imbalance in the gut microbiota, has been linked to IBS, particularly in individuals with IBS-diarrhea. Regular exercise can promote the growth of beneficial bacteria such as Bifidobacterium and Lactobacillus, which have been associated with improved gut health and reduced symptoms of IBS[143]. By enhancing microbial diversity, exercise may improve gut barrier function, reduce inflammation, and help regulate gut motility, all of which contribute to symptom relief in IBS patients[36].

Low- to moderate-intensity aerobic activities like walking, jogging, cycling, and swimming are typically the most effective for improving gut motility, reducing stress, and enhancing overall digestive health. These activities promote regular bowel movements and can help alleviate constipation and diarrhea in IBS patients[144]. These low-impact, mind-body exercises are particularly beneficial for IBS sufferers, combining physical movements with relaxation techniques. Yoga helps reduce stress, improves gut motility, and alleviates symptoms of bloating, cramping, and abdominal pain[145]. Certain yoga poses, such as twists, can promote digestion by stimulating the digestive organs. Resistance exercises or strength training may also benefit IBS patients, as building muscle mass can improve overall metabolic health and reduce stress. Strength training has been shown to enhance insulin sensitivity and improve GI function in some individuals. However, it should be performed at a moderate intensity to avoid overexertion, which can potentially worsen symptoms[146].

While exercise offers many benefits for managing IBS, individuals must tailor physical activity to their specific symptoms and conditions. Intense or vigorous exercise can sometimes worsen symptoms, particularly without proper hydration or on an empty stomach[138]. To maximize the benefits of exercise while minimizing potential discomfort, individuals with IBS should start with low to moderate-intensity activities and gradually increase the intensity as tolerated. It is also advisable to avoid exercising immediately after meals, as this can exacerbate bloating and abdominal discomfort[147]. Staying well-hydrated and maintaining balanced electrolyte levels are crucial, as dehydration can trigger GI distress. Additionally, incorporating stress management techniques, such as mindfulness, deep breathing, or yoga, alongside exercise can help further alleviate IBS symptoms and improve overall well-being[148]. Table 5 summarizes some studies of the effects of physical activity on IBS symptoms and outcome.

Exercise and IBD: Emerging evidence supports the role of exercise in the prevention and management of IBD, particularly Crohn’s disease (CD) and ulcerative colitis (UC) (Table 6). Several cohort studies and reviews have identified that physical activity, particularly at moderate intensity, exerts anti-inflammatory, psychological, and functional benefits that are relevant across various stages of IBD[149]. A prospective cohort study by Khalili et al[150] found an inverse association between physical activity and the risk of CD in women, suggesting a potential preventive role for regular exercise in IBD development. Interestingly, this association was not seen for UC, highlighting disease-specific differences in pathophysiology. Similarly, Wang et al[151] conducted a meta-analysis that confirmed the protective association for CD, particularly among European populations, while again finding no significant relationship with UC.

On a mechanistic level, exercise appears to modulate immune and inflammatory responses in IBD. According to Bilski et al[149], myokines released during exercise can downregulate pro-inflammatory adipokines and cytokines such as tumor necrosis factor-α, contributing to reduced intestinal inflammation. These effects may be mediated through the regulation of mesenteric fat, an active player in Crohn’s pathogenesis. Additionally, moderate exercise has been shown to improve gut barrier integrity, potentially by upregulating tight junction proteins, thereby reducing intestinal permeability and endotoxemia[149,152].

A cross-sectional study by Holik et al[153] further demonstrated that daily physical activity was associated with more persistent remission in therapy-free adult IBD patients, indicating long-term stabilizing effects. Complementing this, Legeret et al[154] reported that long-term moderate-intensity exercise in children with IBD led to reductions in inflammatory markers such as C-reactive protein, erythrocyte sedimentation rate, and thrombocytes, while also improving exercise capacity, indicating that the anti-inflammatory benefits of exercise are age-transcendent and dose-responsive[154]. Beyond inflammation, Engels et al[152] and Narula and Fedorak[155] highlighted exercise’s benefits on fatigue, bone mineral density, and psychological well-being, all of which are compromised in chronic IBD. This is particularly relevant in the context of corticosteroid use and disease-related nutrient malabsorption, which predispose patients to osteoporosis. Weight-bearing and resistance exercises, therefore, offer specific benefits in maintaining skeletal health[152,155]. Despite its benefits, exercise must be carefully tailored to disease activity and patient tolerance. As discussed by Ordille and Phadtare[156], while low-to-moderate intensity exercise is generally safe and beneficial, high-intensity exercise may trigger immune shifts and microbiota alterations that could potentially exacerbate inflammation in susceptible individuals. Hence, individualized regimens, adjusted for disease severity, nutritional status, and surgical history are essential.

Finally, yoga and Tai Chi, which blend physical activity with stress reduction, have demonstrated particular promise for symptom control by modulating the gut-brain axis, reducing cortisol levels, and improving overall mental health[157]. This is of high relevance given the established link between psychological stress and IBD flares. Therefore, regular moderate-intensity exercise offers multifaceted benefits for IBD patients, including reduced inflammation, improved barrier integrity, better mental health, and enhanced quality of life. However, exercise programs should be guided by healthcare professionals, particularly during flares or in post-surgical settings, to ensure both safety and efficacy in IBD management[155].

**Diverticular ** Diverticular disease includes a spectrum of conditions ranging from asymptomatic diverticulosis (the presence of small pouches, or diverticula, in the colon wall) to diverticulitis (inflammation or infection of these pouches). It is a common GI condition, particularly in older adults, and is influenced by factors such as diet, lifestyle, and physical activity[158]. Exercise is critical in preventing diverticular disease, reducing symptom severity, and improving overall GI health. Regular exercise is a valuable tool for preventing and managing diverticular disease, encompassing conditions such as diverticulosis (the presence of small pouches in the colon wall) and diverticulitis (inflammation or infection of these pouches)[159]. Physical activity helps improve gut motility and reduces constipation, which is a major risk factor for the formation of diverticula. Constipation and straining during bowel movements increase intraluminal pressure in the colon, contributing to the development of diverticula over time[160]. Aerobic exercises such as walking, jogging, cycling, and swimming enhance colonic transit, preventing stool stagnation and reducing the likelihood of straining[144]. Exercise also lowers systemic inflammation, which contributes to the progression from asymptomatic diverticulosis to diverticulitis. Regular physical activity can help decrease the risk of inflammation or infection in the diverticula by reducing pro-inflammatory cytokines and improving immune function[161].

Additionally, exercise supports weight management, which is crucial for preventing diverticular disease, as obesity, particularly abdominal obesity, is a known risk factor for diverticulitis and its complications[162]. Exercise mitigates both the mechanical and inflammatory risks associated with diverticular disease by promoting weight loss and reducing visceral fat[159]. For individuals recovering from an episode of diverticulitis, low-impact activities such as walking, yoga, or gentle stretching are beneficial for maintaining mild gut motility and reducing stress without exacerbating symptoms. Once inflammation has resolved, gradual resumption of moderate-intensity exercises can prevent recurrence and improve overall health. Regular exercise also lowers the risk of complications, such as perforation or abscess formation, by enhancing gut motility and reducing strain on the colon wall[163].

Aerobic exercises, resistance training, and low-impact activities like yoga are particularly effective in managing diverticular disease and promoting recovery[164]. Exercise improves colonic motility, reduces inflammation, and helps maintain a healthy weight, thereby lowering the risk of developing diverticula and preventing complications[159]. Tailored exercise regimens that align with individual health status can ensure optimal benefits, supporting long-term GI health while minimizing the risk of symptom exacerbation[163]. Table 7 summarizes the studies on physical activity and diverticular disease.

**Exercise and GI ** GI bleeding, which can occur in the upper or lower GI tract, is a significant medical condition with symptoms ranging from mild anemia to severe hemorrhage. Exercise, particularly endurance or high-intensity physical activities, has been associated with both an increased risk of GI bleeding and potential benefits in preventing its underlying causes. Understanding the relationship between exercise and GI bleeding is critical for promoting safe and effective physical activity, especially in individuals with predisposing conditions or a history of GI bleeding[9].

Endurance exercise, such as marathon running, has been linked to an increased risk of GI bleeding, primarily due to the physiological and mechanical stress it places on the GI system[3]. During intense physical activity, splanchnic hypoperfusion occurs, as blood is diverted from the GI tract to the muscles and other vital organs. This ischemic state can damage the mucosal lining, particularly in the stomach and small intestine, leading to erosions and ulcers that may result in GI bleeding[9,165]. Additionally, prolonged endurance exercise increases gastric acid secretion, which can further compromise the mucosal barrier and increase the risk of upper GI bleeding. Lower digestive tract symptoms are associated with a high risk of GI bleeding, especially during intense exercise, such as marathon runners[166]. For example, in one case study, a 30-year-old male cyclist experienced melena (black, tarry stools) due to gastric ulcers following vigorous exercise, which resolved with proton pump inhibitors and moderated physical activity[167]. Another 33-year-old marathon runner had ischemic colitis after marathon running and presented as three bouts of diarrhea; all occurred after competitive marathon runs[168].

Mechanical factors, such as the jostling of the stomach during high-impact activities like running, can exacerbate mucosal injury. NSAIDs, commonly used by athletes to manage pain and inflammation, compound this risk by inhibiting prostaglandin synthesis, which is crucial for maintaining the protective mucosal lining of the GI tract. NSAID use, combined with intense exercise, has been linked to erosive gastritis and GI bleeding in runners, as highlighted in a case where a 33-year-old female experienced significant blood loss. Symptoms resolved with cessation of exercise and histamine 2-receptor antagonist therapy[169].

Endurance athletes may develop erosions or ulcers in the stomach or duodenum, resulting in symptoms such as hematemesis (vomiting blood) or melena (black, tarry stools)[9]. Colonic ischemia, particularly during prolonged physical activity, can cause rectal bleeding or hematochezia (bright red blood in the stool). Mechanical trauma or irritation to the colon, along with splanchnic hypoperfusion, contributes to this phenomenon. For example, ischemic colitis was observed in a 21-year-old soccer player following vigorous physical activity, which resolved with supportive care and hydration[82].

Moderate physical activity, in contrast to intense endurance exercise, can have protective effects against certain causes of GI bleeding. By promoting overall cardiovascular health, exercise improves intestinal blood flow during rest and reduces the risk of conditions like ischemic colitis, a potential cause of lower GI bleeding[14]. Regular moderate exercise also reduces systemic inflammation, enhances gut motility, and helps prevent constipation, which can contribute to hemorrhoids or anal fissures, common causes of minor lower GI bleeding[144].

Exercise is also associated with better management of risk factors for GI bleeding, such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease[170]. By maintaining a healthy weight and improving metabolic health, exercise reduces the likelihood of variceal bleeding caused by portal hypertension, a complication of liver disease. Studies show that long-distance runners frequently exhibit asymptomatic GI bleeding identified through stool occult blood tests, with no clinical anemia observed in most cases[171,172]. However, the risk is dose-dependent, as running greater distances or at higher intensities increases the likelihood of bleeding[166]. It is recommended to consider GI endoscopy in long-distance runners with GI symptoms and/or anemia before starting treatment[173].

Several precautions are recommended to ensure safe exercise for individuals at risk of GI bleeding. First, exercise intensity should be tailored to the individual’s condition, with high-intensity or prolonged endurance activities avoided in those with a history of GI bleeding or risk factors such as NSAID use or peptic ulcers[46]. Low- to moderate-intensity exercises are safer and still provide significant health benefits. Timing meals appropriately is also important, as exercising immediately after large meals can increase gastric acid secretion and reflux, potentially aggravating upper GI bleeding[51]. Maintaining adequate hydration is essential, particularly during exercise in hot or humid conditions, to reduce the risk of ischemia and its associated complications[174]. Additionally, the use of NSAIDs should be minimized or avoided before exercise to prevent mucosal injury and bleeding, with alternatives like acetaminophen being safer for managing pain[175]. Lastly, individuals with a history of GI bleeding, such as from peptic ulcers or colonic ischemia, should consult a healthcare provider before initiating an exercise program to ensure safety and proper guidance. For individuals recovering from GI bleeding, engaging in gentle, low-impact exercises like walking, yoga, or Tai Chi can aid in overall recovery without placing undue stress on the GI system[56]. As recovery progresses, gradual increases in exercise intensity under medical supervision can promote cardiovascular health and reduce the risk of conditions predisposing to bleeding, such as obesity or portal hypertension[112]. Moderate exercise also enhances the gut microbiota and reduces systemic inflammation, supporting long-term GI health[1]. Table 8 shows the studies concerned with relation of GI bleeding with exercise.

Constipation: Constipation, characterized by infrequent bowel movements, difficulty passing stool, or a sensation of incomplete evacuation, is a common GI complaint affecting individuals of all ages. While dietary factors, hydration, and underlying medical conditions play significant roles in constipation, regular exercise is widely recognized as an effective and natural strategy for improving bowel function. Physical activity promotes intestinal motility, enhances stool passage, and alleviates the discomfort associated with constipation[36].

Exercise positively influences bowel function through several mechanisms. First, physical activity stimulates intestinal motility by increasing the activity of the smooth muscles in the GI tract, facilitating the movement of stool through the colon[176]. Aerobic exercises, such as walking, jogging, and swimming, are particularly effective in speeding up colonic transit time, which can help reduce the time stool spends in the colon, preventing excessive water absorption and hardening of stool[144]. Additionally, exercise enhances blood flow to the GI organs, which supports optimal digestion and gut health. Strengthening the abdominal and pelvic floor muscles through specific exercises, such as yoga or Pilates, can further improve the efficiency of bowel movements by supporting the physical mechanisms involved in stool passage. Exercise also promotes overall metabolic health, reducing stress and improving psychological well-being, both of which can significantly impact gut function, as stress is a known contributor to constipation[177].

Various types of exercise can effectively alleviate constipation by promoting intestinal motility and improving overall bowel function. Aerobic exercises, such as walking, running, cycling, or swimming, are particularly beneficial, as they stimulate intestinal activity and help relieve constipation; even a daily 20-30 minutes walk can significantly improve bowel regularity[178]. Yoga is another effective option, with certain poses, such as spinal twists, seated twists, and forward bends, massaging the abdominal organs, increasing blood flow, and stimulating bowel activity[179]. Strength training, including core-focused exercises like planks and Pilates, strengthens the abdominal and pelvic muscles, supporting efficient bowel movements. Additionally, stretching and gentle movements such as Tai Chi and light stretching enhance circulation, reduce stress, and indirectly improve gut health, making them valuable for managing constipation[180].

To achieve the best results, individuals with constipation should aim for at least 150 minutes of moderate-intensity aerobic exercise per week, as recommended by global health guidelines[181]. Consistency is key, as regular physical activity has cumulative benefits for GI health. Starting with gentle activities like walking and gradually incorporating more intense or targeted exercises, such as yoga or resistance training, can be particularly beneficial[112].

Timing exercise appropriately can also enhance its effects; for example, engaging in physical activity shortly after meals can stimulate the gastrocolic reflex, promoting bowel movements. Maintaining proper hydration during exercise is equally important, as dehydration can worsen constipation by hardening stool. Beyond improving bowel regularity, exercise addresses several underlying factors that contribute to constipation[178]. Physical activity helps maintain a healthy weight, reduces abdominal fat that may compress the intestines, and improves metabolic conditions such as diabetes, which can impair gut motility[182]. Moreover, the stress-reducing effects of exercise can alleviate functional constipation, as psychological stress often exacerbates symptoms[183]. Table 9 summarizes some of the studies concerned with the effects of exercise on constipation. Furthermore, Table 10 shows different exercises contraindicated in specific GI diseases, the reason for contraindication, and any possible modifications. Table 11 also shows the recommended exercises for specific GI diseases.

Exercises that improve GI health

Exercise is vital in promoting GI health. It helps regulate gut motility, improve digestion, reduce inflammation, and enhance gut microbiota diversity. Regular physical activity can have both direct and indirect positive effects on various aspects of GI function[1]. Some types of exercise can specifically improve GI health. Aerobic activities such as walking, jogging, cycling, swimming, and dancing are particularly beneficial for GI health. Aerobic exercise helps improve gut motility, which is crucial for regular bowel movements and preventing constipation[36]. Regular aerobic exercise promotes increased intestinal blood flow, supporting nutrient absorption and overall gut function. Additionally, aerobic exercise can help reduce IBS symptoms and improve gut microbiota composition, increasing the diversity of beneficial bacteria such as Bifidobacteria and Faecalibacterium. It improves gut motility, reduces bloating and constipation, supports healthy microbiota, and reduces IBS symptoms[5].

Resistance training or strength exercises, such as weightlifting and bodyweight exercises, also benefit gut health. While they may not directly impact gut motility like aerobic exercise, strength training improves muscle strength, which can help support the abdominal muscles and reduce symptoms of bloating and discomfort[184]. Resistance training can also improve insulin sensitivity and digestive efficiency and reduce the risk of metabolic disorders affecting GI health. It enhances abdominal muscle strength, supports digestive efficiency, and improves insulin sensitivity, indirectly benefiting GI function[185].

Yoga is particularly beneficial for gut health because it combines controlled breathing with stretching and relaxation. Specific yoga postures, especially those that involve gentle twists, can help stimulate digestion by increasing blood flow to the intestines and improving intestinal motility[186]. Yoga can also reduce stress and anxiety, which are known to exacerbate GI disorders like IBS and GERD[141]. Studies have shown that yoga can help reduce bloating, cramping, and discomfort by promoting relaxation and easing GI muscle tension. It enhances digestive function, improves motility, reduces stress-induced GI symptoms, and alleviates bloating and discomfort[187]. Like yoga, Pilates is a low-impact exercise focusing on core strength, flexibility, and controlled breathing. Pilates strengthens the muscles around the abdomen, improving overall abdominal function and reducing symptoms like bloating and indigestion. The breathing techniques used in Pilates help enhance oxygenation to the gut, supporting better digestion and reducing stress, which can improve conditions like GERD and IBS. Pilates improves abdominal muscle function, enhances gut motility, and alleviates stress-related GI symptoms[188]. Tai Chi is a slow, controlled movement that promotes relaxation and balance. This exercise has been shown to positively affect the gut-brain axis, reducing stress and promoting overall GI health[180]. Tai Chi can help alleviate symptoms of IBS by improving digestion, reducing bloating, and promoting regular bowel movements. The slow, focused movements enhance blood flow to the intestines and can support the functioning of the digestive system[189]. Tai Chi reduces stress, enhances circulation to the gut, promotes relaxation, and can improve digestion and reduce IBS symptoms[190].

Walking is one of the simplest and most accessible forms of exercise that can significantly improve gut health. It enhances intestinal motility, improves circulation to the digestive organs, and helps regulate bowel movements, preventing constipation[178]. Walking also reduces stress and encourages relaxation, which can improve conditions such as IBS and acid reflux. Walking improves digestion, prevents constipation, enhances blood flow to the intestines, and alleviates stress-induced GI symptoms[191]. Cycling is a low-impact aerobic exercise that promotes blood flow to the GI organs and helps regulate bowel movements. Like walking, cycling can improve gut motility, reduce constipation, and alleviate symptoms of IBS. It also improves cardiovascular health, indirectly supporting better GI function by promoting overall health. Cycling enhances circulation to the intestines, improves gut motility, and reduces constipation[192]. While HIIT may not be ideal for everyone, it can benefit gut health in moderation. HIIT involves short bursts of intense exercise followed by periods of rest. This type of training can improve gut motility, reduce visceral fat (which can negatively impact digestion), and promote better nutrient absorption[36]. However, it’s crucial for individuals prone to GI issues to carefully monitor the intensity of HIIT, as excessive intensity can trigger GI distress in some individuals. HITT improves gut motility, aids in fat loss (reducing abdominal fat), and enhances nutrient absorption with moderate intensity[193]. Table 12 summarizes the different exercises that could improve the general health of the GI tract.

Prevention and management strategies of exercise-induced GI disorders

**Dietary ** Dietary adjustments are essential for preventing and managing exercise-induced GI symptoms. The timing and composition of pre-exercise meals, the strategic use of low-residue diets, and the avoidance of trigger foods play crucial roles in minimizing GI distress and improving exercise performance[194]. The timing of food intake relative to exercise is critical to reduce GI symptoms like bloating, cramping, nausea, and reflux. Consuming large meals immediately before exercise can delay gastric emptying and lead to discomfort due to undigested food remaining in the stomach[48]. To minimize these issues, athletes and exercisers are advised to eat their last large meal 3-4 hours before exercise. This allows sufficient time for digestion, reducing the risk of reflux and bloating. For those needing energy closer to exercise, a small, low-fat, low-fiber snack can be consumed 30-60 minutes before physical activity to provide fuel without overloading the digestive system[195]. The composition of pre-exercise meals is equally important. High-fat and high-fiber foods are known to slow gastric emptying and increase the likelihood of GI discomfort during exercise. High-fat meals require longer digestion times, while high-fiber foods can increase bulk and gas production in the intestines. Instead, pre-exercise meals should focus on easily digestible carbohydrates (e.g., white rice, toast, and bananas) and moderate amounts of lean protein to provide energy without overloading the gut. For endurance athletes, liquid-based nutrition such as smoothies or sports drinks can be an alternative to solid foods, reducing the risk of GI symptoms[196].

Adopting a low-residue diet in the 24-48 hours leading up to prolonged or high-intensity exercise can help minimize GI symptoms. A low-residue diet limits fiber intake, reducing the volume of undigested material in the intestines and decreasing stool bulk[197]. This strategy is particularly beneficial for endurance athletes prone to lower GI symptoms such as diarrhea or cramping during long events like marathons or triathlons. Foods suitable for a low-residue diet include refined carbohydrates (e.g., white bread, white rice, and pasta), lean proteins (e.g., poultry and fish), and low-fiber fruits (e.g., bananas and peeled apples). In addition to reducing fiber, avoiding common trigger foods can further alleviate GI symptoms[198]. Trigger foods vary among individuals. High-fat foods slow digestion and increase the risk of nausea and reflux. High-fiber foods increase gas production and intestinal motility, leading to bloating and cramping. Dairy products may trigger lactose intolerance and can exacerbate symptoms like bloating, cramps, and diarrhea[199]. Excess fructose, often found in energy drinks or gels, can overwhelm the small intestine’s absorptive capacity, causing diarrhea. In addition, caffeine and spicy foods can stimulate gut motility and irritate the GI lining, increasing the likelihood of symptoms such as diarrhea or reflux[200].

Athletes and active individuals can implement specific dietary strategies to optimize GI health and exercise performance to alleviate the effect on the GI tract. Athletes can eat large meals 3-4 hours before exercise and small, low-fat snacks 30-60 minutes prior if needed[201]. They should reduce fiber intake 24-48 hours before long or intense exercise to decrease stool bulk and lower GI symptoms. They should keep a food and symptom diary to identify and avoid specific foods that provoke GI distress. They can replace solid foods with liquid-based nutrition when tolerability is an issue, especially during endurance events[202].

**Hydration and ** Hydration and electrolyte balance prevent exercise-induced GI distress and optimize performance. Adequate fluid intake and electrolyte replenishment support normal GI function, enhance digestion and help maintain overall health during physical activity. Dehydration and electrolyte imbalances, common during prolonged or high-intensity exercise, can exacerbate GI symptoms such as nausea, bloating, cramping, and diarrhea[48]. Proper hydration before, during, and after exercise is essential for maintaining normal GI function. Dehydration reduces plasma volume, leading to decreased blood flow to the GI tract, impairing nutrient absorption and slowing gastric emptying, contributing to nausea, bloating, and discomfort. Additionally, dehydration can lead to constipation and abdominal cramps, especially during endurance events. Therefore, athletes are advised to begin exercise in a well-hydrated state by drinking fluids throughout the day and consuming water or sports drinks in the hours leading up to physical activity[203].

During exercise, fluid replacement should be based on sweat rate, exercise intensity, and environmental conditions. For moderate exercise, water is typically sufficient to maintain hydration. However, during prolonged or intense activities, especially in hot and humid conditions, the body loses water and electrolytes such as sodium, potassium, and magnesium through sweat[204]. These electrolytes are essential for maintaining fluid balance, nerve function, and muscle contraction. Athletes risk electrolyte imbalances without proper replenishment, leading to GI distress, muscle cramps, and impaired performance. For prolonged or intense exercise, particularly events lasting more than an hour, oral rehydration solutions (ORS) are highly beneficial. ORS typically contains water, glucose, and key electrolytes like sodium and potassium, which enhance fluid absorption and help restore electrolyte balance. These solutions prevent dehydration, improve gastric tolerance, and enhance performance by maintaining electrolyte balance and fluid volume. By promoting rapid absorption of fluids and electrolytes in the small intestine, ORS reduces the risk of symptoms like bloating, nausea, and cramps that can arise from drinking plain water alone during extended physical activity[205,206]. In addition to maintaining hydration, ORS can help prevent hyponatremia, a condition caused by low sodium levels due to excessive water consumption during exercise without adequate electrolyte replacement[207]. This condition can lead to symptoms ranging from mild nausea and dizziness to severe complications such as seizures and coma. Therefore, athletes should use ORS or electrolyte-rich beverages during prolonged endurance events (e.g., marathons and cycling races) to replenish fluid and electrolytes[204].

To optimize GI function and prevent hydration-related GI symptoms during exercise, athletes should hydrate themself before, during, and after exercise. Drinking 16-20 ounces of water 2-3 hours before exercise is better to ensure adequate hydration levels. In addition, for activities lasting more than an hour, it is better to consume 6-8 ounces of water or sports drinks every 15-20 minutes, adjusting intake based on environmental conditions and sweat rate. After finishing the exercise, athletes should replenish themselves with fluids and electrolytes to promote recovery, aiming to compensate for 1.5 liters of fluid per kilogram of body weight lost during exercise[208]. In endurance events or prolonged training sessions, use ORS that contain electrolytes to prevent dehydration and balance sodium and potassium levels. However, water intake should be balanced with electrolyte consumption to prevent dilutional hyponatremia, especially in long-duration activities[53].

**Training ** Training adaptations are crucial in preventing exercise-induced GI distress and improving tolerance to physical activity. A gradual increase in exercise intensity is one of the most effective strategies to enhance GI function during exercise[209]. By allowing the body to adapt to the physical and physiological demands of exercise over time, athletes can reduce the likelihood of developing GI symptoms such as nausea, cramping, bloating, and diarrhea[210]. One of the primary mechanisms behind exercise-induced GI distress is the sudden physiological stress placed on the digestive system, especially during high-intensity or prolonged activity[39]. During intense physical exertion, blood flow is redirected away from the GI tract to support the muscles, heart, and lungs. This reduction in splanchnic blood flow can impair digestion, slow gastric emptying, and increase intestinal permeability, leading to common symptoms like nausea and abdominal cramping[27]. Additionally, mechanical stress from repetitive jostling during high-impact activities such as running can exacerbate GI discomfort[3].

By gradually increasing exercise intensity, athletes can allow their bodies to adapt to these stressors, thereby improving GI tolerance over time. For example, a runner may start with shorter, lower intensity training sessions, progressively increasing the distance and intensity as the body becomes accustomed to the demands of longer, more vigorous exercise[211]. This gradual adaptation helps minimize the risk of ischemic stress, improves blood flow regulation to the GI tract during exercise, and enhances overall digestion and absorption of nutrients. As training intensity increases, the GI system also adapts to exercise demands[212]. For instance, endurance athletes can gradually condition their bodies to better handle the mechanical jostling of running or cycling. This can reduce symptoms such as diarrhea and cramping, common in long-distance events. Over time, the digestive system becomes more resilient to these stresses, enabling athletes to perform at higher intensities with fewer GI disturbances. Additionally, gut training is an integral part of building GI resilience. This involves conditioning the digestive system to tolerate specific foods, hydration strategies, and supplementation protocols used during exercise. By incorporating these strategies during training, athletes can identify optimal nutrition plans, improve absorption, and reduce the likelihood of exercise-induced GI symptoms[61]. For example, an athlete may experiment with different energy gels, electrolyte drinks, or carbohydrate-rich foods during training to determine which products are best tolerated during exercise. Consistency is key to improving GI tolerance[213]. Regular and progressive training helps to maintain and build the GI tract’s ability to handle the mechanical, metabolic, and physiological demands of exercise. The body adapts to these stressors more with consistent exercise, allowing athletes to push their limits without experiencing significant GI distress[214]. Furthermore, consistency in training, hydration, and nutrition helps athletes fine-tune their approach, ensuring they can perform at their best during competitions and training sessions[202].

**Pharmacological ** Pharmacological interventions can be effective tools in managing exercise-induced GI distress, particularly when dietary and training adjustments alone are insufficient. Medications such as anti-diarrheal agents, antacids, and probiotics can help alleviate symptoms such as diarrhea, acid reflux, and discomfort, allowing athletes to maintain their training routines and performance without being hindered by GI disturbances[215]. Diarrhea during exercise can be caused by a combination of factors, including increased intestinal motility, reduced splanchnic blood flow, and the mechanical jostling of the gut[3]. Anti-diarrheal medications, such as loperamide (Imodium), are commonly used to manage exercise-induced diarrhea, a frequent complaint among endurance athletes, particularly runners. Anti-diarrheals work by slowing intestinal motility and increasing water absorption, thus reducing the frequency and urgency of bowel movements[216]. These medications can be particularly helpful before long-distance events or high-intensity training sessions where the risk of diarrhea is higher. However, athletes should use anti-diarrheal agents cautiously, as overuse can lead to constipation, and they should be taken with careful consideration of the timing of exercise to avoid any potential side effects. In addition, athletes should ensure that they are not masking an underlying condition, such as IBS, that may require further evaluation and more specific treatment. Anti-diarrheals should be seen as a short-term solution to manage symptoms, not a long-term treatment[217].

Antacids, such as calcium carbonate or magnesium hydroxide, are used to alleviate acid reflux or heartburn, which can occur during high-intensity or prolonged exercise. The mechanical stress from activities like running or heavy lifting increases intra-abdominal pressure, which can lead to GERD symptoms, including heartburn and regurgitation[218]. Antacids work by neutralizing stomach acid, relieving discomfort caused by acid irritation of the esophagus. For athletes prone to reflux, using antacids before or during exercise may help control symptoms. However, long-term or excessive use of antacids is not recommended, as it can interfere with nutrient absorption and cause other digestive issues. Antacids are typically used for acute relief, and athletes should address the underlying causes of GERD, such as meal timing, food choices, and exercise intensity, to prevent recurrence of symptoms[51].

Probiotics are live microorganisms that can provide health benefits when consumed in adequate amounts, particularly for maintaining a healthy gut microbiota. In the context of exercise-induced GI symptoms, probiotics have shown promise in promoting intestinal balance, reducing inflammation, and improving gut barrier function[219]. Exercise, particularly intense or prolonged activity, can lead to gut dysbiosis, an imbalance of gut microbes that may increase intestinal permeability (“leaky gut”) and trigger GI symptoms such as bloating, cramping, and diarrhea[49]. Probiotics, such as Lactobacillus and Bifidobacterium strains, help restore balance to the gut microbiota, supporting the digestive system’s ability to handle exercise-related stress. Studies have shown that probiotics can reduce the incidence of antibiotic-associated diarrhea, alleviate IBS symptoms, and improve gut motility in athletes[220]. For athletes, taking probiotics regularly or before events may help reduce the frequency of GI issues, improve recovery, and enhance overall gut health. Probiotics may be particularly beneficial in individuals who have a history of GI distress or who engage in high-intensity training sessions. However, not all probiotics are equally effective for everyone, as the strains’ effectiveness can vary. It is essential for athletes to experiment with different probiotic strains and consult with healthcare providers to determine the most suitable type and dosage[221].

Personalized exercise strategies in GI disorders

Personalizing exercise interventions is critical to optimizing GI outcomes while minimizing potential adverse effects. Given the heterogeneity of GI disorders, stratifying exercise recommendations based on disease severity, gut microbiota profiles, age, functional capacity, and comorbid conditions is essential for tailoring safe and effective programs.

For individuals with GERD, the severity of symptoms should guide exercise choices. Patients with mild GERD often tolerate moderate-intensity aerobic activities such as brisk walking or cycling, particularly when performed at least two hours after meals. These activities support weight loss and enhance LES tone[98]. In contrast, patients with moderate GERD may benefit from low-impact exercises such as swimming or yoga, with caution to avoid poses that increase intra-abdominal pressure. During active flares or in cases of severe GERD, gentle practices like stretching or Tai Chi are preferable, as they reduce physical strain while supporting stress relief[222].

Similarly, exercise recommendations for IBD must be individualized based on disease activity. During remission, moderate aerobic exercise, resistance training, and mind-body activities like yoga can improve quality of life, reduce systemic inflammation, and enhance bone mineral density[223]. However, during active disease flares, lower-intensity activities such as gentle stretching, walking, or Tai Chi are more appropriate to prevent exacerbating intestinal symptoms and systemic fatigue. Caution is advised with high-intensity or endurance activities, which may exacerbate gut permeability and inflammation[156].

The selection of exercise type and intensity is also crucial in IBS. Regular moderate-intensity exercise, including activities such as walking, yoga, and swimming, has been shown to alleviate common IBS symptoms like abdominal pain, bloating, and irregular bowel habits[224]. High-intensity exercise, while beneficial for cardiovascular health, may worsen symptoms in some IBS patients due to heightened visceral sensitivity. Therefore, exercise programs should emphasize consistency, gradual progression, and stress-reduction components to effectively support gut-brain axis regulation in IBS[36].

Exercise prescriptions may also be informed by an individual’s gut microbiota profile, an area of growing interest. For those with dysbiosis, marked by low microbial diversity or reduced SCFA production, moderate aerobic exercise can help increase beneficial bacteria such as Faecalibacterium prausnitzii, which contribute to gut barrier integrity and immune regulation[69]. These interventions are most effective when paired with dietary strategies such as prebiotics or probiotics. Conversely, individuals with a balanced microbiota may tolerate a broader range of exercises, including resistance training, which can further support metabolic health[225]. In patients with inflammatory microbiota profiles, such as those with IBD, low-impact and anti-inflammatory modalities like yoga and walking are generally better tolerated and may help attenuate mucosal inflammation[226].

Age and physical conditioning are additional important factors. In children and adolescents, activity should be playful and enjoyable, focusing on natural movement and stress relief through swimming, dance, or active games[227]. Adults with GI disorders should follow standard physical activity guidelines, 150 minutes of moderate aerobic exercise weekly combined with strength training, while tailoring activities around symptom triggers and disease-specific needs[112]. In older adults, low-impact activities like yoga, Tai Chi, and aquatic exercise help support bowel regularity and preserve mobility without increasing the risk of GI symptoms or falls[228].

Comorbidities must also be considered. In patients with obesity, low-impact aerobic activities can reduce intra-abdominal pressure and improve motility. Those with osteoporosis, especially in the context of IBD or long-term corticosteroid use, benefit from supervised, low-risk resistance and balance exercises to prevent bone loss and falls[152]. For individuals experiencing anxiety or depression, mind-body approaches such as yoga, breathing techniques, and Tai Chi are effective in modulating the gut-brain axis and alleviating both psychological and GI symptoms[38]. Meanwhile, patients with malnutrition or frailty may require shorter, lower-intensity sessions with nutritional support to avoid fatigue or catabolism[229]. Ultimately, this stratified approach underscores the need for interdisciplinary collaboration among gastroenterologists, physiotherapists, and dietitians. Exercise regimens should be regularly reassessed and adapted based on symptom progression, treatment response, and lifestyle factors to ensure sustainable and individualized care for patients with GI disorders.

Research gaps and future directions

While significant progress has been made in understanding the impact of exercise on GI health, several key areas remain underexplored and warrant further investigation. Future research should focus on addressing the long-term effects of exercise on GI health, exploring the role of individualized nutrition and hydration strategies, investigating microbiota-targeted therapies, and conducting large-scale, high-quality studies to enhance our understanding of exercise-GI interactions. Much existing research on exercise and GI health focuses on acute symptoms that occur during or immediately after exercise, such as nausea, bloating, and diarrhea. However, there is a significant gap in our understanding of the long-term effects of exercise on GI health, particularly in athletes and highly active individuals. While moderate, consistent exercise is known to have protective effects on gut motility and microbiota diversity, the potential for chronic GI issues resulting from excessive or prolonged high-intensity training remains largely unaddressed. Research into the long-term impact of splanchnic hypoperfusion, repeated ischemia, and chronic GI inflammation on gut integrity, nutrient absorption, and the development of GI diseases such as IBD or IBS is needed. Longitudinal studies examining the cumulative effects of high-endurance training and recovery strategies are critical to better understanding how long-term exercise may benefit and challenge GI health.

Nutrition and hydration are critical components of managing exercise-induced GI symptoms, yet the role of individualized nutrition and hydration strategies remains underexplored. Many of the current recommendations focus on generalized guidelines for meal timing, hydration, and electrolyte replenishment, but these strategies are often not tailored to the unique needs of each individual. Factors such as age, sex, training history, exercise type, and GI conditions influence how an individual’s digestive system responds to exercise. Future research should investigate personalized approaches to nutrition and hydration, considering factors like an athlete’s microbiome composition, metabolic rate, and exercise intensity. For example, identifying the optimal composition of pre-exercise meals (carbohydrates, proteins, and fats) and post-exercise recovery drinks for different types of athletes could help reduce the incidence of GI distress. Similarly, personalized hydration plans that account for individual sweat rates and electrolyte loss during exercise are crucial to improving both performance and GI comfort.

Microbiota-targeted therapies, including probiotics and prebiotics, have emerged as promising for improving gut health and mitigating exercise-induced GI symptoms. While probiotics have been shown to improve gut barrier function, reduce inflammation, and promote microbial diversity[230], there is still a need for more research to identify which specific strains of probiotics are most effective for athletes with different GI profiles. Similarly, the role of prebiotics, non-digestible food components that promote the growth of beneficial gut bacteria, has not been fully explored in exercise. Prebiotics, often found in high-fiber foods, could enhance gut health and performance by promoting the growth of beneficial species like Bifidobacterium and Faecalibacterium[231]. Moreover, the potential of synbiotics (a combination of probiotics and prebiotics) as a therapeutic strategy for exercise-induced GI distress has been largely overlooked. Understanding how specific prebiotic and probiotic interventions can optimize gut health and minimize GI symptoms during exercise is an area of high research potential. Studies exploring the impact of these therapies in combination with training regimens and their effects on athletes with pre-existing GI conditions (such as IBS or IBD) could lead to targeted recommendations for improving gut resilience.

While the field of exercise and GI health has grown, large-scale, high-quality studies are still lacking. Most research conducted thus far has focused on small sample sizes or has been observational in nature. RCTs examining the direct effects of exercise on GI health and the impact of interventions such as hydration strategies, dietary changes, and microbiota-targeted therapies are essential to establish evidence-based recommendations. Additionally, studies should assess the long-term outcomes of exercise on GI health, particularly in the context of elite athletes who undergo intense training and competition. There is also a need for more diverse study populations, including different age groups, sexes, and individuals with varying fitness levels, as these factors can influence how exercise affects GI function. Future research should aim to standardize protocols for measuring exercise-induced GI symptoms and develop a better understanding of the mechanisms behind these symptoms. This would allow researchers to identify the most effective interventions and refine strategies that help athletes and active individuals optimize their exercise routines without suffering from debilitating GI distress.

Recommendations: Based on the findings of this study, several recommendations are proposed to enhance the understanding and management of the relationship between exercise and GI health. Tailored exercise programs should be developed to address the specific needs and conditions of individuals with GI diseases, adjusting the intensity, type, and duration of exercise to minimize adverse effects while optimizing benefits. Moderate-intensity aerobic exercises, such as walking, cycling, and swimming, are particularly effective for promoting gut motility, reducing systemic inflammation, and alleviating stress without exacerbating symptoms. Mind-body exercises like yoga, Tai Chi, and Pilates should also be integrated into GI disease management plans, as they combine physical benefits with stress reduction, a key factor in managing many GI conditions. Proper timing and nutrition are essential, with patients encouraged to avoid exercising immediately after meals and to ensure adequate hydration before and during physical activity to prevent symptoms such as bloating or reflux.

Additionally, more high-quality, large-scale studies are needed to establish evidence-based guidelines for the role of exercise in preventing and managing specific GI disorders, focusing on long-term effects, gut microbiota interactions, and integration with dietary and pharmacological treatments. Healthcare providers should be educated on the benefits and risks of exercise for GI health, enabling them to offer informed recommendations and design holistic management plans. Public awareness initiatives should highlight the role of regular physical activity in preventing common GI conditions such as constipation, reflux, and obesity-related disorders. By implementing these strategies, both patients and healthcare providers can harness the benefits of exercise to improve digestive health and overall quality of life.

Limitations: This systematic review has several limitations that should be considered when interpreting its findings. First, the existing literature on the relationship between exercise and GI health is highly variable, with differences in study populations, exercise modalities, and intensity levels making it difficult to draw definitive conclusions. Many studies rely on self-reported data for outcomes such as symptom relief, exercise adherence, and dietary habits, which are subject to recall bias and variability in individual perception. Additionally, objective measures, such as validated tools for assessing GI health or biomarkers of gut function, are inconsistently used, limiting the ability to standardize findings across different studies. Another key limitation is the lack of research on the long-term effects of exercise on specific GI disorders. While short-term benefits and risks are frequently discussed, there is limited evidence on how exercise influences chronic conditions such as IBD, IBS, or GERD over extended periods. Furthermore, few studies account for the potential confounding effects of lifestyle factors such as diet, sleep patterns, and stress, which play a significant role in both exercise responses and GI health. Understanding these interactions is crucial for developing personalized recommendations. Finally, publication bias may influence the current body of evidence, as studies reporting positive effects of exercise on GI health are more likely to be published, while neutral or negative findings may be underrepresented. Future research should focus on large-scale, longitudinal studies using standardized methodologies, objective physiological measures, and comprehensive lifestyle assessments to provide a more holistic understanding of how exercise affects GI health.

CONCLUSION

This systematic review underscores the critical role of exercise as a non-pharmacological intervention for optimizing GI health. Regular physical activity, particularly moderate-intensity aerobic exercises such as walking, cycling, and swimming, demonstrates significant benefits across various GI conditions, including GERD, IBS, IBD, peptic ulcers, diverticular disease, and constipation. Exercise improves intestinal motility, enhances gut barrier function, reduces systemic inflammation, and promotes a balanced gut microbiota, while also alleviating stress, a common exacerbating factor for many GI disorders. While moderate-intensity activities are generally beneficial, high-intensity or prolonged exercise can exacerbate symptoms in conditions like GERD and IBD, highlighting the importance of tailoring exercise regimens to individual needs. Mind-body activities such as yoga and Tai Chi further support GI health by addressing the gut-brain axis and promoting relaxation. Despite these benefits, variability in individual responses underscores the need for personalized exercise recommendations based on specific GI conditions, baseline fitness levels, and co-existing factors such as diet and stress. Future research should focus on addressing existing gaps, including the long-term effects of exercise on GI health, the role of gut microbiota modulation, and the interplay between exercise, diet, and pharmacological therapies. By advancing our understanding in these areas, healthcare providers can develop more comprehensive, evidence-based guidelines to harness the therapeutic potential of exercise in managing GI disorders, ultimately improving patient outcomes and quality of life.