These days, there’s a lot of focus on gut health. No wonder! The gut is command central for brain health and a healthy immune system. Scientists point out that 70% of your immune system lies in your gut. Also, your brain and gut influence each other through a nerve called the vagus nerve.
The human body contains trillions of microorganisms (bacteria, viruses, and fungi), which are collectively known as microbiota or microbiome. They live on the skin, in your mouth and nose, gut (intestine) and vagina, etc. These microbes help with digestion, provide nutrients to your body, and protect your gut against harmful bacteria.
Among the most important of these ecosystems is the gut microbiome, a community of bacteria, trillions of them, that live in your digestive tract. It’s this ecosystem of organisms that help digest your food, absorb nutrients, produce certain vitamins, and shield your gut against other pathogenic organisms. It also helps to regulate your immune system, which is why the microbiome is so important to our overall health and well-being.
Sometimes called the “second brain,” the gut microbiome plays a role in your mental health too. Most of these microbes are beneficial, while some can cause problems if they get out of balance or take over the intestine due to certain factors like medication use or poor diet choices.
Does the Gut Microbiome Affect Exercise Performance?
With the wide variety of roles that gut microorganisms play in health and well-being, you might wonder whether they can affect exercise performance. One factor that can dramatically change the composition of the gut microbiome and do it quickly is taking antibiotics.
Antibiotics are one of the most common medications for treating bacterial infections, but they can also have unintended consequences. Antibiotics can damage the gut microbiome and disrupt your body’s natural balance of bacteria, which is critical to health.
Antibiotics kill bacteria by stopping them from making new cells and growing. But this also means that any beneficial bacteria in the gut may be killed off as well. This creates an imbalance that can cause gastrointestinal problems like diarrhea, constipation, and bloating.
But can disrupting your gut microbiome by taking antibiotics also affect your performance when you exercise? At least in mice, it can. In a study, researchers gave two groups of mice bred to enjoy running a 10-day course of antibiotics and monitored their fecal samples.
Although the mice appeared outwardly well, the amount of time they ran dropped by 21% after taking antibiotics. Here’s another surprising finding. The mice hadn’t recovered their normal running behavior even after 12 days off the antibiotic. The effects of antibiotics on the gut microbiome can linger for months after taking a single course. Although this was a mouse study, the researchers believe that mice and humans are so similar in their physiology that these results could apply to humans too.
How the Gut Microbiome Could Affect Exercise Performance
Although scientists in this study don’t know the mechanism by which changes to the gut microbiome affect exercise performance and motivation, they have a theory. Gut bacteria break down carbohydrates into metabolites that your body can use to fuel exercise. So, gut-friendly bacteria may provide cells with the fuel they need while taking antibiotics disrupts the availability of these metabolic products.
Another study found that some long-distance runners and endurance athletes have more of a bacteria called Veillonella in their guts. By giving these bacteria to mice, researchers found the mice could run on a treadmill for 14% longer. These bacteria produce a compound called propionate that boosts exercise capacity and performance.
The mechanism by which propionate improves exercise capacity is interesting. Veillonella bacteria use lactic acid as their fuel source. As you know, lactic acid is a by-product of glucose produced under anaerobic (low oxygen) conditions. When you do high-intensity exercise, lactic acid builds up so fast that your body can’t clear it all and you become fatigued. Veillonella bacteria can latch onto the lactic acid that builds up during exercise and use it as a fuel source. How is that beneficial? As they remove lactic acid from your bloodstream, it helps reduce muscle fatigue, allowing you to perform better during exercise.
Therefore, having certain types of bacteria as part of your gut microbiome, like Veillonella, could give your exercise performance a boost. There’s also some evidence that exercise itself can improve the composition of your gut microbiome. The bugs in your gut are sensitive to the foods you eat and signals from your environment. Until we know about what the ideal gut microbiome composition is, here are some ways to keep your gut microbiome as healthy as possible:
- Limit inflammatory foods.
- Consume prebiotic foods, rich in fermentable fiber
- Enjoy more fermented foods, particularly fermented vegetables
- Avoid taking antibiotics unless you need them. (They don’t work for viruses)
- Stay physically active
The Bottom Line
A healthy gut microbiome is important for brain and immune health, and antibiotics can disrupt your gut microbiome – and having a healthy gut microbiome could also give exercise performance a boost. What’s more, exercise appears to improve the health of the gut microbiome too.
References:
- Monica P. McNamara, Marcell D. Cadney, Alberto A. Castro, David A. Hillis, Kelly M. Kallini, John C. Macbeth, Margaret P. Schmill, Nicole E. Schwartz, Ansel Hsiao, Theodore Garland. Oral antibiotics reduce voluntary exercise behavior in athletic mice. Behavioural Processes, 2022; 199: 104650 DOI: 10.1016/j.beproc.2022.104650.
- Rettner R. How This Gut Bacteria May Give Elite Athletes an Edge. livescience.com. Published June 24, 2019. Accessed July 14, 2022. https://www.livescience.com/65780-athletes-gut-bacteria-boost-performance.html
- “Exercise and Gut Bacteria – Healthline.” 24 Sept. 2018, https://www.healthline.com/health-news/exercise-improves-your-gut-bacteria.
- “Antibiotic Do’s & Don’ts | Antibiotic Use | CDC.” https://www.cdc.gov/antibiotic-use/do-and-dont.html.
- “Antibiotics – Common Side Effects, Allergies, and Reactions.” 15 Sept. 2021, https://www.drugs.com/article/antibiotic-sideeffects-allergies-reactions.html.
- “Microbiotic Fuel | Harvard Medical School.” 02 Jul. 2019, https://hms.harvard.edu/news/microbiotic-fuel.
- Scheiman, J., Luber, J.M., Chavkin, T.A. et al. Meta-omics analysis of elite athletes identifies a performance-enhancing microbe that functions via lactate metabolism. Nat Med 25, 1104–1109 (2019). https://doi.org/10.1038/s41591-019-0485-4.
- Gut S. Propionate Secreted by Gut Bacteria Enhances Exercise Capacity. Fight Aging! Published July 2, 2019. Accessed July 25, 2022. https://www.fightaging.org/archives/2019/07/propionate-secreted-by-gut-bacteria-enhances-exercise-capacity/
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