Your lack of motivation to exercise may be influenced by gut bacteria, researchers say

Feeling unmotivated to exercise? It might not be your fault but in fact gut microbes in your body, according to a recent study published in Dec. 2022, by researchers at the University of Pennsylvania. 

After researchers analyzed mice running on a treadmill looking at at how long it took before the animals exhausted themselves, they found that the gut microbiome — a makeup of trillions of microbes living in your gut — contributed more to motivation to exercise than genetic, metabolism or even behavior attributes.

Researchers found that when they used antibiotics on mice to eliminate these gut microbes, the mice tired themselves out quicker and voluntarily ran on the wheel less. 

Scientists explain that motivation is controlled in a region of the brain known as the striatum. Striatum are activated by dopamine which provides feelings of reward, which is found in runners high. Dopamine essentially enhances the desire to exercise. 

When mice who’s been given the antibiotic to deplete microbiome levels, they produced decreased levels of dopamine compared to normal mice. Giving mice dopamine blockers also exhausted mice quicker and made them less motivated to exercise. 

The next phase of the experiment involved finding other gut microbes that stimulated sensory neurons to produce dopamine to improve motivation for tasks like exercise. That’s when they identified a compound known as fatty acid amides (FAAs). 

Adding these FAAs to the diets of microbiome-depleted mice restored their motivation for exercise. 

The results suggest that diet could improve one's motivation to exercise. 

"If we can confirm the presence of a similar pathway in humans, it could offer an effective way to boost people’s levels of exercise to improve public health generally," said study lead Dr. Christoph Thaiss.