Why Working Out Is Good for Your Gut Microbiome
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Rachel Feltman: For American scientist‘s Science quickly, I am Rachel Feltman.
Over the past two decades, few scientific subjects have made a greater traditional splash than the microbiome. Our growing understanding of the microbes that live on us, in us and around us, scientists analyze – and try to modify – from the colonies of our armpits to our genitals. But when most of us hear the word “microbiome”, our minds go to various ecosystems found in our guts.
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Communities of bacteria, archaea, viruses and fungi that live in our digestive paths have a huge impact on us. Research shows that our intestinal microbiomas influence the way we digest our food and absorb nutrients, and an imbalance in intestine microorganisms is associated with conditions such as type 2 diabetes and non-alcoholic liver disease. Some research even suggests that our intestinal microbiomas are linked to cognitive function and mental well-being: scientists explore how autism spectrum disorder, depression, anxiety, SSPT and more could be linked to tiny creatures that live in us.
But this relationship is not unilateral: we also have a lot of power over our intestinal microbiomas – and this extends beyond our food choices.
Our guest today is Lydia Denworth, a contributor editor for American scientist. She writes SciamColumn science of health science. In the June 2025 issue of the magazine, she reported on the surprising link between intestinal and exercise microbes. It is here today to tell us more.
Thank you very much for coming to discuss with us today.
Lydia Denworth: It’s good to be here.
Feltman: So you have recently written in your column on the microbiome, which, of course, have heard a lot of speaking, but I think people tend to think of their microbiome and think of yogurts and probiotics. But you wrote on the link with the exercise. How did you meet this connection for the first time?
Denworth: I was at a conference as a scientific journalist, and I heard Marc Cook Talk – this is one of the people I interviewed for this column – and he is a researcher in North Carolina [Agricultural and Technical] State University, and he studies exercise in the microbiome, and that’s exactly what you just said who interested him.
I mean, everyone thinks of diet, probiotics, things like that. And back about 15 years ago, he was at the University of Illinois [Urbana-Champaign] Getting your doctorate, and the idea that there could be a link between exercise and microbes in your intestine was really not something that someone thought. But he knew that people with inflammatory intestine disease, in particular ulcerative colitis, benefited from the exercise. So he thought: “Well, let me investigate, perhaps, what it is.”
So he stuck mice on wheels – you know, the mice like to run on wheels – and he found that the mice who voluntarily exercised were protected against a version of colitis and those that did not work. And so it started there, with this idea that: “Oh, there is more to look at.”
Feltman: So now, you know, more than a decade later, what do we know about the link between exercise and the intestinal microbiome?
Denworth: We know two things. So, one thing is: in people who are regular exercises or who are elite athletes, the diversity and abundance of microbes in your intestine are greater, but more important than this is: “What do the microbes really do?” And this is where the researchers really went down the rabbit burrow and said: “Well, why would the exercise improve your physical form?”
And what they have found is that the exercise stimulates the production of microbes which produce something called short chain fatty acids. And it’s a simple molecule, but it’s something that helps your intestinal health. It helps reduce inflammation. This is part of your healthy metabolism. Thus, metabolism makes energy, on the right, and when you exercise, then you increase these short chain fatty acids, in particular that called butyrate, it improves all these processes that your body must do to stay healthy.
Feltman: Can you tell us a little more about the functional differences in the microbiomas of people who get this boost of the exercise compared to right? You know, what does this diversity of microbes do for us?
Denworth: There are a lot of things that we don’t know exactly what microbes do in relation to the other advantages of the exercise, so there are open questions there. But having this healthy and active microbiome they see in athletes and the exercise seems to increase your exercise capacity. It probably works in both directions – it is bidirectional.
Thus, the search on the other side is only really in the mouse so far. But they note that if, for example, you give antibiotics to mice who kill bacteria in their guts, they are less likely to exercise and they reach exhaustion more quickly. They also note that a healthy microbiome seems to contribute to muscle development – then vice versa, on the right: you do not develop as many muscles as effectively if you do not have a healthy microbiome.
And so all this is at the first stages of research, but it is – it’s intriguing, right?
Feltman: Yes, and the researchers behind it have specific recommendations for what type of exercise or how much is, you know, help your microbiome?
Denworth: Until now, research does not really change the standard recommendations, namely that we are committed to about 150 minutes of moderate exercise per week or 75 minutes of intense exercise per week. Research suggests that its aerobic exercise is more than strength training which has this effect – although it is so early and there have been so few studies of other types of exercises other than aerobic that I think we do not know with certainty that this does not happen with other forms of exercise, but the aerobic exercise is where it is. The recommendations are the same; It’s just more reason to go out and empty your training [laughs].
Feltman: [Laughs] Absolutely. And remind us what are the general advice to support a good diversified and healthy intestinal microbiome?
Denworth: Well, the diet is the first thing that affects your microbiome – more powerfully than exercise, I should say that – and fibers in particular are really important to have a good healthy intestine. But then the exercise – probably combine a healthy diet which includes a lot of fiber and doing a good aerobic exercise will be the best combination that will give you the healthiest intestine.
Feltman: Great, so just more motivation to do the things we already know are good for us [laughs].
Denworth: [Laughs] That’s exactly it.
Feltman: Well, thank you very much for joining us today. It was great.
Denworth: Thank you for doing me.
Feltman: That’s it for today’s episode. To find out more about this subject, see the Lydia column online or in print. If you don’t read already American scientistThe printed magazine, you can probably find it on a newspaper kiosk near you – or go to Scienticamerican.com/GetSciam to subscribe. If you like this show, you will absolutely love the rest of the American scientist family. As of Science quickly, We will be back on Friday to talk about a new insidious trend in the health of men.
Science quickly is produced by me, Rachel Feltman, with Fonda Mwangi, Kelso Harper, Naeem Amarsy and Jeff Delviscio. This episode was published by Alex Sugiura. Shayna has and Aaron Shattuck checks our show. Our theme music was composed by Dominic Smith. Subscribe to American scientist For new scientists up to date and in -depth.
For Scientific American, Here is Rachel Feltman. See you next time!
