You might pop a probiotic or chug some kombucha in pursuit of better gut health. But increasingly, research suggests you should hit the gym, too.
The gut is a “trainable organ,” explained John Hawley, PhD, head of the Exercise & Nutrition Research Program at Australian Catholic University. And, according to a research review that Hawley recently published, the gut can be trained just like the rest of your body: through exercise.
Your gastrointestinal system is home to trillions of microorganisms, such as bacteria, fungi, and viruses. Collectively, this is known as the gut microbiome.
Cultivating a flourishing, diverse gut microbiome seems to translate to a range of health benefits. The gut microbiome is involved in digestion, metabolism, immunity, and the development—or, potentially, prevention—of a range of diseases, research suggests.
Researchers are still learning about exactly how to optimize gut health, but it’s well-established that diet and medication usage play a role in shaping this community of microorganisms. More recently, studies have shown that exercise has an impact, too.
Anyone who’s been on a long, grueling run knows that intense exercise can wreak havoc on the gut in the short term. But behind that temporary discomfort lies potentially profound benefits, Hawley told Health.
Animal studies dating back almost 20 years have found that exercise promotes beneficial changes in rodents’ gut microbiomes. And in one of the first human studies on this topic, published in 2014, researchers found that, compared to non-athletes, rugby players had more diverse gut microbiomes—a key marker of good gut health.
Among other effects, physical activity seems to boost levels of microbes that produce short-chain fatty acids that support gastrointestinal health, reduce inflammation, and perhaps even help protect against diseases like colon cancer, explained Sara Campbell, PhD, who directs the Exercise and Gastrointestinal Health Laboratory at Rutgers University-New Brunswick.
This is a relatively new area of study, so scientists are still learning a lot. But “years of research have very consistently found, in both human and animal models, that these changes occur positively in both men and women,” Campbell told Health.
It’s unclear what these microbiome changes mean for human health, but researchers are actively exploring their impact on everything from inflammatory bowel disease to cardiovascular disease to cancer.
“People who are physically active have reduced rates of colon cancer,” said Jeffrey Woods, PhD, a professor of health and kinesiology at the University of Illinois at Urbana-Champaign. “Exercise-induced changes in the gut microbiota and its products might be one reason why, but this remains to be tested.”
Researchers are still trying to answer that question, Hawley said. But his recent paper suggests that “cross-talk“ between muscles and the rest of the body may be an important factor.
When you exercise, Hawley explained, your muscles release a host of particles that enter the bloodstream and travel to other organs. That process helps explain why organs throughout the body benefit from physical activity, Hawley said.
“The kidney or the liver isn’t exercising when you go out for a run, yet we know that you get a healthier liver and a healthier kidney,” he said. The same seems to be true for the gut microbiome.
And, Campbell added, the relationship seems to work both ways: exercise benefits the gut, and a healthy gut benefits exercise capacity. “When we knock microbes out, at least in animal models, [the animals] aren’t able to exercise as well,” she explained.
In short, the gut and the rest of the body seem to be in constant conversation, working in tandem.
More research is needed to make exact recommendations about the kind of workout your gut needs, Campbell said. But the research does provide some clues.
“Endurance—and not resistance—exercise seems to impart the biggest effect on the gut microbiome,” Woods explained.
Studies have linked running and cycling to beneficial gut changes, but a 2024 research review found limited published evidence in favor of resistance training. (Campbell said she’d like to see more studies on that topic.)
You don’t have to be a marathon runner to see beneficial changes from cardio, Woods’ research suggests. In one small study he co-authored, lean but previously sedentary adults experienced positive microbiome shifts after just six weeks of running or cycling three times per week, for 30–60 minutes at a time.
“That is good news because most people can do that type of activity,” Woods told Health.
Experts often say the best exercise routine is the one you’ll actually stick to—and that seems to be the case where gut health is concerned.
“Once you stop exercising…your gut microbiota will revert back to what your individual normal flora looks like,” Campbell says. “You have to maintain the exercise to maintain the benefits, which is typical of most everything.”
