Most of us don’t need to be told more than once that exercise is good for our health. Regular physical activity has been associated with reduced inflammation, increased mood and metabolism, as well as an overall boost in longevity and wellbeing. Yet despite hearing physicians extol the benefits of regular exercise for many years now, some of us still need a little extra push to get off the couch and into the gym. Luckily, science is here to provide that nudge, with a growing body of research suggesting many of the benefits of exercise – spanning from the physiological to the psychological – may be attributable to changes in the composition and functional capacity of the gut microbiota.

Dr. Woods’ study shows that physical exercise can induce changes in gut microbiota composition

A study, previously covered on the blog and led by researchers at the University College Cork (UCC) in Ireland, showed that the gut microbiota of elite rugby players was significantly more diverse than that of non-athlete, age-matched, healthy controls. When it comes to maintaining gut bacterial diversity, there are few factors more within our control than the foods we eat. With athletes being a generally a health-conscious bunch, it is unsurprising that the rugby players enrolled in the study ate a balanced diet rich in prebiotic fiber, making it difficult for scientists to conclude that exercise alone caused the differences they observed.

For scientists, the question is whether you can achieve elite athletes’ performance levels by simply modifying the gut microbiota

In order to address this limitation, we turn to a second study, published in the Journal of Medicine & Science in Sports & Exercise, and led by Dr. Jeffrey Woods of the University of Illinois at Urbana-Champaign. In this study, lean and obese adults continued with their usual diets while researchers investigated the effects of endurance training on their microbiota composition. The two groups were shown to have different gut microbiota composition at baseline, prior to starting the prescribed exercise regime. Following 6 weeks of endurance training, the gut microbiota of the two groups began to change, and after a 6-week washout period where subjects were instructed to return to their previous sedentary lifestyles, these changes were reversed.

Dr. Woods’ study provides compelling evidence that exercise can induce changes in gut microbiota composition independent of diet. This is leading scientists to wonder whether changes in the gut microbiota could be a key part of the mechanism explaining why exercise is so good for our health.

Many of us may now be wondering – can changing our microbiota to resemble that of an elite athlete help us perform like one too? It’s an intriguing question, and one that we will have to wait for scientists to answer. While more research is done however, one thing remains certain – whether we are new to the gym or a future Olympic hopeful – exercise is good for our health!



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Allen JM, Mailing LJ, Niemiro GM, Moore R, Cook MD, White BA, Holscher HD, Woods JA, Exercise Alters Gut Microbiota Composition and Function in Lean and Obese Humans. Med Sci Sports Exerc. 2018 Apr;50(4):747-757. doi: 10.1249/MSS.0000000000001495.

Codella R, Luzi L,Terruzzi I, Exercise has the guts: How physical activity may positively modulate gut microbiota in chronic and immune-based diseases. Dig Liver Dis. 2018 Apr;50(4):331-341. doi: 10.1016/j.dld.2017.11.016. Epub 2017 Nov 28.