How Exercise Intensity Affects Your Gut Microbiome

Engaging in regular physical activity benefits both mental well-being and physical health, but recent research from Edith Cowan University (ECU) highlights that the intensity of exercise may significantly influence the health of your gut microbiome. Ph.D. candidate Bronwen Charlesson led a study exploring how different training loads impact gut bacteria, revealing that both high and low exercise intensities can alter gut health markers.

Previous studies have shown that athletes tend to have a distinct gut microbiota compared to the general population, characterized by increased short-chain fatty acids, greater microbial diversity, and specific bacterial abundance differences. Charlesson’s research suggests that these differences are not solely due to diet but are also linked to fitness markers like oxygen uptake.

The study, published in the Journal of the International Society of Sports Nutrition, indicates that training load influences gut bacterial composition, notably in the concentration of short-chain fatty acids and the presence of certain bacteria species. One possible mechanism involves higher blood lactate levels produced during intense exercise, which may be transported to the gut and metabolized by bacteria, thereby impacting gut flora.

Interestingly, the research observed that during periods of lower training load, athletes often adopt relaxed dietary habits, consuming more processed foods, fewer fruits and vegetables, and slightly more alcohol. These dietary shifts, along with slower gut transit times, further contribute to changes in the gut microbiome during rest periods.

While the precise role of the gut microbiome in athletic performance remains to be fully understood, preliminary evidence suggests it could be involved in lactate metabolism and pH regulation, both critical for optimal performance. Future studies are necessary to better understand how training intensity, diet quality, and gut transit time can be managed to support athletes' health and performance.

Overall, maintaining a balanced training load and diet may be key to promoting a healthy gut microbiome, which could, in turn, enhance athletic performance and overall well-being.

Source: https://medicalxpress.com/news/2025-08-intensity-impacting-gut.html