Exercise Boosts Gut Health, Independent of Diet
Scientists offer the first definitive evidence that exercise alone can change the composition of microbes in the gut. The study was designed to isolate exercise-induced changes from other factors, such as diet or antibiotic use, that might alter the intestinal microbiota.
In the study, published in the journal Medicine and Science in Sports and Exercise, researchers tracked changes in the composition of gut microbiota in human participants as they transitioned from a sedentary lifestyle to a more active one – and back again.
“These are the first studies to show that exercise can have an effect on your gut independent of diet or other factors,” said Jeffrey Woods, a University of Illinois professor who led the research with former doctoral student Jacob Allen.
The research team recruited 18 lean and 14 obese sedentary adults, sampled their gut microbiomes, and started them on an exercise program during which they performed supervised cardiovascular exercise for 30-60 minutes three times a week for six weeks. The researchers sampled participants’ gut microbiomes again at the end of the exercise program and after another six weeks of sedentary behaviour. Participants maintained their usual diets throughout the course of the study.
To earn the benefits of exercising, you need to keep exercising… Forever and ever, and ever…
Fecal concentrations of SCFAs, in particular, butyrate, went up in the human gut as a result of exercise. These levels declined again after the participants reverted to a sedentary lifestyle. Genetic tests of the microbiota confirmed that this corresponded to changes in the proportion of microbes that produce butyrate and other SCFAs.
So to earn the benefits of exercising, you actually have to keep exercising.
The most dramatic increases were seen in lean participants, who had significantly lower levels of SCFA-producing microbes in their guts to begin with. Obese participants saw only modest increases in the proportion of SCFA-producing microbes. The ratios of different microbes in the gut also differed between lean and obese participants at every stage of the study, the researchers said.
“The bottom line is that there are clear differences in how the microbiome of somebody who is obese versus somebody who is lean responds to exercise,” Woods said. “We have more work to do to determine why that is.”
Materials provided by University of Illinois. Note: Content may be edited for style and length.