Exercise can change the makeup of the microbes in our gut.
According to Jeffrey Woods, lead researcher in two studies, one in mice and the other in humans, exercise can have an impact on your gut independent of diet or other factors.
In the first study, Woods and colleagues transplanted fecal material from exercised and sedentary mice into the colons of sedentary germ-free mice, which had been raised in a sterile facility and had no microbiota of their own. In the exercise mice they found a reduction in inflammation and an increase in the regenerative molecules that promote a faster recovery.
In the second study, the team 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.
The scientists looked at the microbes in the participants’ guts using fecal samples immediately after their exercise programme and then again after six weeks of not working out. They discovered that after weeks of exercise, people’s concentrations of butyrate – a special type of fatty acid that helps with the reduction of inflammation and the production of energy – went up. These concentrations soared in leaner participants while there was a modest increase among the obese participants of the study. The two studies were designed to isolate exercise-induced changes from other factors — such as diet or antibiotic use — that might alter intestinal microbiota.
“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.”