Can Exercise Boost My Gut Health?

There’s a lot going on when you exercise — you move more oxygen through the bloodstream and to the brain, your core body temperature heats up, and your blood flow redirects to different organs. Researchers suspect these conditions can help gut bacteria flourish, though the exact mechanisms remain unclear, says Taylor Valentino, PhD, a postdoctoral researcher at the University of Utah in Salt Lake City, where he studies the relationship between muscle development and the microbiome.

“Exercising causes important changes that help gut microbes to bloom and convert, and, coinciding with that, we get molecules our bodies can use,” Dr. Valentino says. Here’s a breakdown of the research that explores how exercise and the gut may be linked, as well as steps you can take to help nurture a lively gut microbiome through your workouts.

Can Exercise Boost Gut Health?

Most gut bacteria have a symbiotic relationship with the body: In short, you nourish and feed them, and they produce vitamins, fatty acids, and amino acids that your body uses for things like immune function, digestion, mood regulation, and more.

Regular exercise speeds up the process, increasing the diversity of microbial species in the gut and encouraging bacteria to flourish, says Jacob Allen, PhD, an associate professor of exercise physiology at the University of Illinois in Urbana-Champaign.

And a growing body of research suggests that exercise may well promote a diverse gut microbiome. One caveat as you read on: Most of these studies did not strictly track or control what participants ate. Human microbiomes are highly individual, and diet can make a significant difference. Future trials will benefit from locking down meal plans so researchers can separate exercise-related changes from food-related ones.

Cardio Breeds Bacteria That Turn Waste Into Fuel

A recent review of 89 studies (47 in humans and 42 in animals) found that while high-intensity interval training (HIIT) initially stresses the gut, repeated training appears to promote microbial changes that support this waste-to-fuel conversion.

Moderate-Intensity Exercise Can Reduce Leakage in the Gut Lining

The gut lining, or epithelium, is a vital barrier between your gut and the rest of your body that’s also crucial for absorbing nutrients. Its structure is a mesh of cells.

A review of human clinical and randomized trials found that moderate exercise increased levels of proteins linked to a tighter mesh by 15 to 20 percent and rebalanced inflammatory markers toward a profile suggesting lower inflammation. But moderation is key: The researchers also found that more than 90 minutes of intense exercise loosened the “mesh” of cells, increased inflammatory markers, and led to a temporary increase in “bad” bacteria such as Escherichia coli (E. coli).

Clinical Trials Are Looking at the Link Between Gut Health and Exercise

Several clinical trials are directly assessing the link between physical activity and the diversity of your gut microbes.

This will test the gut’s ability to produce SCFAs in response to exercise without any dietary changes.

High-Volume Endurance Training May Damage the Gut

The relationship between gut health and mood is another significant point. The researchers propose that this gut damage may combine with other factors to affect endurance athletes' mental health, though they're clear this is a hypothesis. Longer-term studies are needed to test whether gut barrier function plays a real role.

Does Good Gut Health Support Exercise?

Veillonella is a microbe that consumes lactate — which our bodies produce during a hard workout — and converts it into propionate, an SCFA that boosts our energy levels. The study authors suggest that exercise increases Veillonella microbes in the gut, providing the extra energy boost needed for endurance running.

5 Ways to Make Your Exercise Routine Gut-Friendly

Research in this area focuses on cardio and consistency.

1. Focus on Cardio

For now, the research connecting exercise to improved gut health has focused mostly on aerobic exercise, and less so on resistance training, like weight lifting. That doesn't mean pumping iron won't help your gut health or lacks other notable benefits. It's just that this area has been studied far less in relation to the gut, Dr. Allen says.

Researchers think part of the reason this works is that harder effort temporarily redirects blood flow away from the digestive tract, and the gut adapts to that mild, repeated stress.

Other exercises, like rowing, swimming, or skipping, can also be effective ways to get your cardio in, Dr. Cook says.

2. Be Consistent

To keep the production of good microbes in your gut going, you’ll need to keep exercising and make it part of your overall lifestyle.

Just like your stamina decreases if you quit running for a few weeks, your gut microbiome will lose out on the production of good microbes once you stop exercising, Cook warns.

3. Start Small

If you’re starting at square one and aren’t used to exercising, ease your way in, Valentino says.

“Don’t go from couch to marathon,” he advises. “The goal is giving your microbiome a constant fuel source through exercise.” This can help you prevent injuries and build a long-lasting, sustainable, enjoyable habit.

4. Get Outdoors

Exposure to nature increases our exposure to diverse ecosystems and the bacteria within them. “If we’re outdoors, running in a park, or along the ocean, we’re breathing in very diverse communities of bacteria that are in the air,” says Christopher Lowry, PhD, a behavioral neuroscientist and an associate professor at the University of Colorado in Boulder, where his research focuses on the gut microbiome and anxiety-related disorders.

5. Don’t Forget Nutrition

Your diet has just as much impact on your gut health as your exercise regime, Cook says. Before you go grocery shopping and meal planning, take note: The gut microbiome loves fermented foods, which contain a variety of bacteria and yeast.

Natural probiotics include:

• Yogurt
• Kefir
• Kombucha
• Miso
• Sauerkraut
• Kimchi