Gut microbes good for marathon runners

by | Exercise and Fitness

Scientists have discovered that long-distance runners harbour colonies of bacteria in their gut that can help them to run for longer.

Research into how the gut microbiome influences health is growing at a rapid pace. The microbiome can weigh up to two kilograms in an adult human. Think of it as not unlike a delicate rainforest ecosystem of plants, animals and insects.

Changes in the gut microbiome have been linked to changes in immune function and even mental health. Now researchers are looking at how the gut microbiome can change in states of good health and for that, some of the fittest people around were the guinea pigs.

The study looked at the microbiome fingerprint in stool samples from 15 elite marathon runners in the lead-up to and after the 2015 Boston Marathon and compared this against 10 sedentary people. A separate study looked at the gut microbiome make-up of 87 ultramarathon runners and Olympic-level rowers.

What stood out was the increase in the bacterium genus of Veillonella. There were much higher levels of this bacterium in the athletes.

Why is this interesting? Because Veillonella has the capacity to metabolise lactate and convert it to an alternative fuel source that can help fuel muscles. This fuel is propionate which can help increase heart rate and increase the maximum rate of oxygen consumption.

Gut microbes help endurance athletes go further

Accumulation of lactate happens when muscles work hard over long distances so it could be that the microbiome adaptation seen here is one that favours fitness by helping to clear the lactate.

The final phase of the study was inoculating the gut of mice with Veillonella. Mice performed 13 percent better on a treadmill test after getting the bacterial boost.

Further support for this new research comes from a study from last year which was the first to show that a 12-week training program causes an improved gut microbiota independent of dietary changes.


For athletes, one of the benefits of endurance training may come from ‘training the gut’ where gut microbes work to help the host run further and faster.

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