Exercise, fitness, and the gut

Cronin, Owen; Molloy, Michael G.; Shanahan, Fergus

doi:10.1097/mog.0000000000000240

Cited by 42 publications

(34 citation statements)

References 90 publications

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“…Exercise and gut symptomatology have long been connected (reviewed by Cronin et al [34]). The bidirectional communication between the ANS and the ENS in the GI tract, the gut-brain axis, mainly occurs by way of the vagus nerve, which runs from the brainstem through the digestive tract (reviewed by Carabotti [35]).…”

Section: Main Textmentioning

confidence: 99%

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

Clark

Mach

2016

Journal of the International Society of Sports Nutrition

388

318

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Fatigue, mood disturbances, under performance and gastrointestinal distress are common among athletes during training and competition. The psychosocial and physical demands during intense exercise can initiate a stress response activating the sympathetic-adrenomedullary and hypothalamus-pituitary-adrenal (HPA) axes, resulting in the release of stress and catabolic hormones, inflammatory cytokines and microbial molecules. The gut is home to trillions of microorganisms that have fundamental roles in many aspects of human biology, including metabolism, endocrine, neuronal and immune function. The gut microbiome and its influence on host behavior, intestinal barrier and immune function are believed to be a critical aspect of the brain-gut axis. Recent evidence in murine models shows that there is a high correlation between physical and emotional stress during exercise and changes in gastrointestinal microbiota composition. For instance, induced exercise-stress decreased cecal levels of Turicibacter spp and increased Ruminococcus gnavus, which have well defined roles in intestinal mucus degradation and immune function.Diet is known to dramatically modulate the composition of the gut microbiota. Due to the considerable complexity of stress responses in elite athletes (from leaky gut to increased catabolism and depression), defining standard diet regimes is difficult. However, some preliminary experimental data obtained from studies using probiotics and prebiotics studies show some interesting results, indicating that the microbiota acts like an endocrine organ (e.g. secreting serotonin, dopamine or other neurotransmitters) and may control the HPA axis in athletes. What is troubling is that dietary recommendations for elite athletes are primarily based on a low consumption of plant polysaccharides, which is associated with reduced microbiota diversity and functionality (e.g. less synthesis of byproducts such as short chain fatty acids and neurotransmitters). As more elite athletes suffer from psychological and gastrointestinal conditions that can be linked to the gut, targeting the microbiota therapeutically may need to be incorporated in athletes’ diets that take into consideration dietary fiber as well as microbial taxa not currently present in athlete’s gut.

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Section: Main Textmentioning

confidence: 99%

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

Clark

Mach

2016

Journal of the International Society of Sports Nutrition

388

318

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“…In this respect, the role of exercise as a modulator of the gut microbiome has received attention as a possibility of reducing the risk for several metabolic, inflammatory and neoplastic diseases for inactive individuals (Pham et al, 2012; van Dijk et al, 2012; Egan and Zierath, 2013; Cronin et al, 2016). Various levels of physical exercise were recently linked to modifications of the microbiota in test-participants (Clarke et al, 2014), increased vagal-nerve tone at rest (Cronin et al, 2016), gene expression of transport proteins (Jayewardene et al, 2016) and exercise related immunological responses (Bermon et al, 2015; Ringseis et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Hypoxia and Inactivity Related Physiological Changes (Constipation, Inflammation) Are Not Reflected at the Level of Gut Metabolites and Butyrate Producing Microbial Community: The PlanHab Study

et al. 2017

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We explored the assembly of intestinal microbiota in healthy male participants during the run-in (5 day) and experimental phases [21-day normoxic bed rest (NBR), hypoxic bedrest (HBR)], and hypoxic ambulation (HAmb) in a strictly controlled laboratory environment, balanced fluid, and dietary intakes, controlled circadian rhythm, microbial ambiental burden, and 24/7 medical surveillance. The fraction of inspired O2 (FiO2) and partial pressure of inspired O2 (PiO2) were 0.209 and 133.1 ± 0.3 mmHg for NBR and 0.141 ± 0.004 and 90.0 ± 0.4 mmHg for both hypoxic variants (HBR and HAmb; ~4,000 m simulated altitude), respectively. A number of parameters linked to intestinal transit spanning Bristol Stool Scale, defecation rates, zonulin, α1-antitrypsin, eosinophil derived neurotoxin, bile acids, reducing sugars, short chain fatty acids, total soluble organic carbon, water content, diet composition, and food intake were measured (167 variables). The abundance, structure, and diversity of butyrate producing microbial community were assessed using the two primary bacterial butyrate synthesis pathways, butyryl-CoA: acetate CoA-transferase (but) and butyrate kinase (buk) genes. Inactivity negatively affected fecal consistency and in combination with hypoxia aggravated the state of gut inflammation (p < 0.05). In contrast, gut permeability, various metabolic markers, the structure, diversity, and abundance of butyrate producing microbial community were not significantly affected. Rearrangements in the butyrate producing microbial community structure were explained by experimental setup (13.4%), experimentally structured metabolites (12.8%), and gut metabolite-immunological markers (11.9%), with 61.9% remaining unexplained. Many of the measured parameters were found to be correlated and were hence omitted from further analyses. The observed progressive increase in two immunological intestinal markers suggested that the transition from healthy physiological state toward the developed symptoms of low magnitude obesity-related syndromes was primarily driven by the onset of inactivity (lack of exercise in NBR) that were exacerbated by systemic hypoxia (HBR) and significantly alleviated by exercise, despite hypoxia (HAmb). Butyrate producing community in colon exhibited apparent resilience toward short-term modifications in host exercise or hypoxia. Progressive constipation (decreased intestinal motility) and increased local inflammation marker suggest that changes in microbial colonization and metabolism were taking place at the location of small intestine.

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“…Shifts in gut microbial communities have therefore been proposed to contribute to the development of obesity. Whether weight loss, either through exercise or calorie reduction, can shift gut microbial communities, specifically during the progression of early life obesity, is completely unknown, yet recent work highlights the importance of elucidating relationships between exercise and gut health in humans (9). A better understanding of how these factors influence the gut at this critical period may offer insight into how they may augment susceptibility to obesity and related metabolic conditions later in life.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Diet versus Exercise on Metabolic Function and Gut Microbiota in Obese Rats

Welly

Liu

Zidon

et al. 2016

Medicine &Amp; Science in Sports &Amp; Exercise

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Cardiometabolic impairments that begin early in life are particularly critical, as they often predict metabolic dysfunction into adulthood. Obesity, high-fat diet (HFD), and inactivity are all associated with adipose tissue (AT) inflammation and insulin resistance (IR), major predictors of metabolic dysfunction. Recent evidence also has associated the gut microbiome with cardiometabolic health. PURPOSE Compare equal energy deficits induced by exercise and caloric reduction on cardiometabolic disease risk parameters including AT inflammation, IR and gut microbiota changes during HFD consumption. METHODS Obesity-prone rats fed HFD were exercise trained (Ex, n=10) or weight-matched to Ex via caloric reduction while kept sedentary (WM, n=10), and compared to ad libitum HFD-fed (Sed, n=10) rats for IR, systemic energetics and spontaneous physical activity (SPA), adiposity, and fasting metabolic parameters. Visceral, subcutaneous, periaortic, and brown AT, liver, aorta, and cecal digesta were examined. RESULTS Despite identical reductions in adiposity, Ex, but not WM, improved IR, increased SPA by ~26% (p<0.05 compared to WM and Sed), and reduced LDL cholesterol (p<0.05 compared to Sed). WM and Ex both reduced inflammatory markers in all AT depots and aorta, while only Ex increased indicators of mitochondrial function in brown AT. Ex significantly increased the relative abundance of cecal Streptococcaceae and decreased S24-7 and one undefined genus in Rikenellacea; WM induced similar changes that did not reach statistical significance. CONCLUSIONS Both Ex and WM reduced AT inflammation across depots, while Ex caused more robust changes to gut microbial communities, improved IR, increased fat oxidation, increased SPA, and increased indices of brown AT mitochondrial function. Our findings add to the growing body of literature indicating that there are weight-loss independent metabolic benefits of exercise.

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Exercise, fitness, and the gut

Abstract: Challenging methodology investigating the relationship between exercise and gut health should not deter from exploring exercise in the promotion of gastrointestinal health.

Cited by 42 publications

References 90 publications

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

Hypoxia and Inactivity Related Physiological Changes (Constipation, Inflammation) Are Not Reflected at the Level of Gut Metabolites and Butyrate Producing Microbial Community: The PlanHab Study

Comparison of Diet versus Exercise on Metabolic Function and Gut Microbiota in Obese Rats

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