March 25, 2016
Can Your Workout Impact Your Gut Health? Yes—And Here's Why
Fungi, protozoans, bacteria, nonliving viruses. It might not be pretty, but the human microbiome is a beautiful thing. The approximately 100 trillion bacteria that live in our gut (and, to a lesser degree, our mouths and skin) boost indispensable functions that support metabolism, immune systems, and mental health. Ever-mounting evidence of the powers of the microbiome — some call it “the forgotten organ” — has the health-conscious among us downing probiotic-packed yogurt drinks and investing in prebiotic supplements. Now, it might have us booking into a Spin class.
The link between physical activity and gut flora was noted two years ago, when researchers published a study comparing the national rugby team of Ireland and sedentary men, which found that the elite athletes had healthier guts. But the study did not control for dietary differences among its subjects, which left room for interpretation. The latest research, however, confirms what the rugby study suggested: We can alter our bacterial structure through exercise.
“That people who move more have a more diverse microbiome is something that we noticed at my lab several years ago, but we couldn’t prove causality,” says Rob Knight, Ph.D., director of the Center for Microbiome Innovation at U.C. San Diego. “These studies are incredibly exciting.” One, published last week in the journal PLOS One, compared two sets of young mice: those that exercised and those that didn’t. Some of the rodents ate a high-fat diet, others, low fat. Over the course of 12 weeks, the rodents that ran on a wheel, regardless of diet type, experienced an increase in several helpful bacteria—some by as much as 40 percent. The study’s lead author, Sara Campbell, Ph.D., at the Department of Exercise Science and Sport Studies at Rutgers University, points out that she found exercise to be extremely effective at raising levels of butyrate, the bacteria that helps protect against colon cancer. “Exercise might also help you feel less bloated,” she says.