But it’s still unclear exactly how exercise causes changes in the community of microorganisms that live in our gut, although there are several theories, Woods said.
“Lactate is produced when we exercise, and it can be fuel for certain species of bacteria,” he says. Another potential mechanism, he explained, could be through exercise-induced changes in the immune system, particularly the gut immune system, because our gut microbes come into direct contact with gut immune cells.
Exercising also causes changes in blood flow to the gut, which can affect the cells lining the gut wall and in turn lead to microbial changes. Hormonal changes caused by exercise can also cause changes in gut bacteria. But none of these potential mechanisms “have been definitively tested”, Woods said.
Some elite athletes often suffer from training stress due to the high-intensity training they perform. As much 20-60% athletes suffer from stress due to overtraining and inadequate recovery, according to some estimates. But the bacteria in our gut can help control the release of hormones triggered by exercise-related stress, while also potentially helping to release mood-boosting molecules. They can also help athletes with some of the intestinal problems they are experiencing. However further research is needed in this area.
But there’s much more we can learn about how our physical activity affects the creatures that live in our guts, such as how different types of exercise and their duration can change microbial communities. It may also differ from individual to individual, based on their existing gut occupant as well as their BMI and other lifestyle factors, such as diet, stress levels, and sleep.
As scientists continue to uncover more and more secrets hidden within our digestive tracts, we may find new ways to improve our health through the vibrant and diverse community of organisms that call us their home.
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