When it comes to staying on top of your game, your gut health may matter just as much as training or nutrition.

The trillions of bacteria, fungi, and other microbes living in your digestive tract are collectively called the gut microbiome. Once considered relevant only to digestion, these microbes are now linked to energy levels, inflammation control, mental resilience, and even post-workout recovery.

While the science is still evolving, early research points to a powerful connection between the gut microbiome and athletic performance.

The gut-performance loop

A stable, well-functioning gut microbiome impacts athletic performance in a positive way.1 But here's the twist – your workouts and meals also shape your gut. Like a feedback loop, what you do on the mat, at the gym, or in the kitchen rewires your microbial profile. In return, your microbiome influences how well your body adapts to physical and mental demands.

This relationship has become a focal point of research. Studies show that the gut microbiome of an athlete differs significantly from a non-athlete – and these differences may enhance metabolism, immune defense, and resilience to stress.1

Microbiome benefits for body and brain

One of the microbiome’s superpowers is producing short-chain fatty acids (SCFAs). Produced through the breakdown of dietary fibers, these beneficial compounds have a number of health-boosting effects, including:

  • Reducing inflammation by improving the gut barrier.1-3
  • Supporting immune defense by regulating T cells.1,2,4
  • Positively impacting metabolism and glucose regulation.1-3

The gut microbiomes of athletes in particular have even more performance boosters. They're more likely to produce compounds like glutathione and taurine, which can help the body recover from the cellular wear-and-tear of tough workouts.5 Veillonella, a microbe more common in athletes, thrives on lactic acid and converts it into a short-chain fatty acid called propionate  – a usable energy source that can also reduce cholesterol.1,6-8

That’s like your gut turning metabolic waste into performance fuel.

But the microbiome’s influence extends beyond the muscles – it reaches the mind, too.

The gut–brain axis – the bidirectional communication system between your digestive tract and central nervous system – plays a role in mood and motivation. Studies in mice show that certain gut microbes lead to a rise in feel-good dopamine during physical activity. This dopamine boost makes exercise more rewarding and helps the mice run longer.9

The gut microbiome also influences neurologic processes related to mental clarity, stress responsiveness, mood regulation, and anxiety management – all crucial elements of keeping it cool under the pressures of training and competition.10

The exercise-microbiome relationship: It’s complicated

Just as the gut can boost your physical performance, exercise is good for the gut... to a point.

Moderate intensity physical activity has been shown to enhance microbial diversity, promoting the growth of beneficial bacteria that support health and metabolism.11,12 But the relationship turns sour with overtraining.

Up to 70% of athletes experience digestive issues from intense or endurance exercise, from heartburn and bloating to diarrhea and bathroom urgency.13 Some of these symptoms may be chalked up to reduced blood flow to the gut, stress, or increased body temperature during competitions.13

But research is also beginning to point to the microbiome. Prolonged high-intensity endurance workouts can compromise gut barrier function, leading to “leaky gut” – a condition where bacteria and toxins seep into the bloodstream, triggering inflammation and fatigue.14

That said, elite athletes tend to have a more diverse and unique set of gut bacteria. These bacteria seem to help the body break down food more efficiently, manage inflammation, and possibly recover better after intense physical activity.5

Eat to compete: Diet, probiotics, and microbial harmony

Of course, a strong gut isn’t built on exercise alone – what an athlete eats matters just as much.

Many sports diets focus on protein, often in the form of powders and shakes. And yes, it's true that athletes need more protein to build and repair muscles. But too much may affect gut health in ways that hurt performance.14

A high-fiber diet full of vegetables, fruits, and healthy fats is a better option to provide the raw materials gut microbiota need to thrive.14,15 Instead of loading up on protein bars, try fueling with real food: think lentils, quinoa, nuts, and leafy greens drizzled with olive oil.

And yes, as you might expect, probiotics are on the menu, too.

Probiotics get a lot of buzz in the athletic world – and for good reason. These “good bacteria” may help reduce muscle soreness, fatigue, and gut issues.14,16 While results vary depending on the specific strain and dose, multi-strain probiotic blends and fermented foods like kefir and yogurt show promise in supporting gut health and potentially boosting performance.*14,16

Just don’t expect miracles from pills alone. Probiotics work best when paired with a well-rounded, fiber-rich diet.14 And as with any supplement, quality and strain matter, so choose a quality product or consult a healthcare professional if you're considering a probiotic.

Train your gut like you train your body

Currently, much of the evidence is indirect, and there are no microbiome therapies or specific probiotics recommended for athletic performance. Still, it's increasingly clear that your gut microbiome is involved in nearly every facet of physical performance, from reducing inflammation to mitigating the stress of competitions. And like any other part of your body, your gut responds to training, nutrition, and recovery.

This doesn't mean you need to trade squats for sauerkraut. But it is an invitation to think of your gut as an active participant in your performance. The next frontier of sports science may not be about more reps or better gear – but smarter, gut-centered strategies for whole-body performance.

A word from Thorne

Like Dr. Bauer explains, taking care of your gut is important – whether you’re an athlete or not. You can explore Thorne’s GI support products or narrow down your search to just probiotics.

One of the favorites among athletes is FloraSport 20B®, which is NSF Certified for Sport®. And if you’re wondering about the bugs living in your own gut, try Thorne’s Gut Health Test that uses cutting edge gene sequencing to analyze your gut microbiome and recommend diet, lifestyle, and supplement solutions. 

References

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  2. Min L, Ablitip A, Wang R, et al. Effects of exercise on gut microbiota of adults: A systematic review and meta-analysis. Nutrients. 2024;16(7):1070.
  3. Hodgkinson K, El Abbar F, Dobranowski P, et al. Butyrate's role in human health and the current progress towards its clinical application to treat gastrointestinal disease. Clin Nutr. 2023;42(2):61-75.
  4. Kim CH. Complex regulatory effects of gut microbial short-chain fatty acids on immune tolerance and autoimmunity. Cell Mol Immunol. 2023;20(4):341-350.
  5. Fontana F, Longhi G, Tarracchini C, et al. The human gut microbiome of athletes: Metagenomic and metabolic insights. Microbiome. 2023;11(1):27.
  6. Hu T, Wu Q, Yao Q, et al. Short-chain fatty acid metabolism and multiple effects on cardiovascular diseases. Ageing Res Rev. 2022;81:101706
  7. Scheiman J, Luber JM, Chavkin TA, et al. Meta-omics analysis of elite athletes identifies a performance-enhancing microbe that functions via lactate metabolism. Nat Med. 2019;25(7):1104-1109.
  8. Sales KM, Reimer RA. Unlocking a novel determinant of athletic performance: The role of the gut microbiota, short-chain fatty acids, and "biotics" in exercise. J Sport Health Sci. 2023;12(1):36-44.
  9. Dohnalová L, Lundgren P, Carty JRE, et al. A microbiome-dependent gut-brain pathway regulates motivation for exercise. Nature. 2022;612(7941):739-747.
  10. Appleton J. The gut-brain axis: Influence of microbiota on mood and mental health. Integr Med (Encinitas). 2018;17(4):28-32.
  11. Dziewiecka H, Buttar HS, Kasperska A, et al. Physical activity induced alterations of gut microbiota in humans: a systematic review. BMC Sports Sci Med Rehabil. 2022;14(1):122.
  12. Mach N, Fuster-Botella D. Endurance exercise and gut microbiota: A review. J Sport Health Sci. 2017;6(2):179-197.
  13. Ribichini E, Scalese G, Cesarini A, et al. Exercise-induced gastrointestinal symptoms in endurance sports: A review of pathophysiology, symptoms, and nutritional management. Dietetics. 2023;2(3):289-307.
  14. Hughes RL, Holscher HD. Fueling gut microbes: A review of the interaction between diet, exercise, and the gut microbiota in athletes. Adv Nutr. 2021;12(6):2190-2215.
  15. Cella V, Bimonte VM, Sabato C, et al. Nutrition and physical activity-induced changes in gut microbiota: possible implications for human health and athletic performance. Foods. 2021;10(12):3075.
  16. Kearns RP, Dooley JSG, Matthews M, et al. Do probiotics mitigate GI-induced inflammation and perceived fatigue in athletes? A systematic review. J Int Soc Sports Nutr. 2024;21(1):2388085.