Exercise can support your digestive health and gut microbiome, but its potential benefits — and risks — vary depending on the type of activity.
When you're dedicated to a fitness routine, you might be able to easily rattle off the main benefits of exercise, from improved cardiovascular health and increased bone mineral density to more functional movement patterns. But its impact on your gut may not come to mind.
Studies suggest exercise can increase the number of beneficial microbial species, enhance microflora diversity, and improve the development of commensal bacteria in the gut (which break down indigestible compounds and defend against pathogens), according to a paper published in Oxidative Medicine and Cellular Longevity.
That said, no two types of exercise are alike. Different intensities of movement influence your gut health and microbiome in unique, and sometimes negative, ways. Here’s what to know, depending on your choice of workout.
Moderate-Intensity Exercise
A moderate-intensity activity program can make your bathroom trips more pleasant, which is one benefit of exercise for your gut. Compared to sedentary people, individuals who engage in moderate-intensity exercise are less likely to suffer from constipation, as the activity stimulates movement of the gut, says Lin Chang, M.D., a gastroenterologist and an associate director of UCLA Health’s Goodman-Luskin Microbiome Center.
Even low-intensity exercise can reduce the amount of time your stool is moving through your digestive tract, which minimizes the amount of contact between pathogens in your body and the gastrointestinal mucus layer, according to the Oxidative Medicine article. In turn, exercise may assist in reducing the risk of colon cancer, diverticulosis, and inflammatory bowel disease, per the researchers.
What’s more, moderate-intensity endurance exercise has been shown to improve the diversity of the gut microbiota, says Chang. Reminder: The gut microbiome (consisting of bacteria, viruses, and other microorganisms) assists in digestion and food absorption for energy production, and its diversity is often viewed as an indicator of its health. Improvements in gut microbiota diversity can minimize inflammation and gastrointestinal symptoms, according to a 2021 review published in Frontiers in Nutrition. On the flip side, “a decreased diversity is often seen in people with chronic illnesses, like IBS or inflammatory bowel disease,” adds Chang.
High-Intensity Exercise
Your gut health may take a hit if you’re a high-performing athlete or practice vigorous-intensity exercise. During high-intensity exercise, more blood is diverted toward your skeletal muscles to assist in the movement, so less blood flows to your gut. In turn, the system slows down, explains Chang. “Your stomach emptying and the transit through the small intestine and large intestine could actually slow, so people can have some nausea or other abdominal symptoms,” she notes.
Vigorous exercise may also increase the permeability of the gastrointestinal epithelial wall, research suggests. “The lining of the gut is part of our barrier to protect us, but when there's increased intestinal permeability, then the immune system in the gut can then respond to what's in the gut, which is the metabolites that the microbes make and the foods that we eat,” says Chan. Increased permeability is present in inflammatory bowel disease, and it’s also been found in individuals with irritable bowel syndrome, alcoholic liver disease, and other conditions. But the jury’s still out on whether there’s a clear cause-and-effect relationship between the weakened barrier and these health concerns, research shows.
That’s not to say you should avoid high-intensity movement entirely. Elite athletes have been found to have greater gut microbial diversity, with more bacterial species that are involved in the production of short-chain fatty acids (a metabolite that’s linked with anti-inflammatory, immunoregulatory, and cardiovascular-protective activities, among others).
Yoga
There isn’t much research into yoga’s impact on gut health, but one small randomized control trial on patients with irritable bowel syndrome found that practicing yoga reduced GI symptoms just as well as eating a low-FODMAP diet, says Chang. (If you’re unfamiliar, a low-FODMAP diet involves restricting your intake of certain short-chain carbs that aren’t absorbed well by the small intestine and may cause digestive distress in some people, including those with IBS.)
The relaxing activity also increases vagal tone, or vagal nerve activity, she says. The vagus nerve carries a variety of signals from the gut (as well as the liver, heart, and lungs) to the brain and vice versa, and it’s the main contributor to the parasympathetic nervous system (aka the “rest and digest” system), according to a review in Frontiers in Psychiatry.
Athletes who engage in high levels of activity generally have greater activity in the sympathetic nervous system (aka the “fight or flight” system), so they’re able to rise up to their challenging workout or sport and perform effectively. “Their sympathetic drive goes up, and that can slow down the gut and affect the permeability and the microbiome,” says Chang. But yoga and other calming forms of movement may have a positive effect on your health. “If you do more of a relaxation [activity] with breathing, like yoga, it increases vagal tone,” she explains. In turn, “the parasympathetic system can help suppress inflammatory response and it also is able to reduce pain response.”
The Bottom Line
While some forms of exercise, such as moderate-intensity exercise and yoga, could be beneficial for your digestive health and gut microbiome, activities on the extreme end of intensity may have potentially harmful impacts. That said, your movement practice isn’t the only element contributing to your gut health. The key to it all: engage in vigorous exercise in moderation and stick with some type of exercise routine, says Chang.
“You can get GI symptoms from extreme exercise, and even more sustained effects from prolonged, repetitive, extreme exercise,” she explains. “But there are other factors that are involved [in gut health], including good sleep, good diet, and drinking plenty of fluids. It's all about a balance.”