Oral Antibiotics May Cause Reduction in Exercise

A study by University of California finds oral antibiotics may reduce exercise. Illustration - Shutterstock

A study by the University of California (UCR) suggests that broad-spectrum oral antibiotics may reduce motivation and endurance for voluntary exercise in humans, with the effects magnified in high-exercise cohorts.

“We believed an animal’s collection of gut bacteria, its microbiome, would affect digestive processes and muscle function, as well as motivation for various behaviors, including exercise,” said Theodore Garland, UCR physiologist on June 1.

The team conducted their study in mice models by wiping out gut bacteria in two groups of mice: one group bred for voluntary exercise and the normal mice that were not.

The mice were fed broad-spectrum oral antibiotics and gut microbiome clearance was confirmed through fecal samples taken 10 days later, with no aerobic bacteria colony detected after fecal samples were plated and incubated.

Though body mass and overall health of the mice remained constant, the authors observed an immediate reduction in running distance and duration for mice bred for voluntary exercise.

Overall running duration and cage activity was also reduced for the control mice that are more sedentary, though the decrease was not significant.

Further, even after the 12 days of recovery period, exercise levels in the voluntary running group did not return to the levels prior to treatment, despite researchers trying to re-introduce the gut microbiota back into the mice’s guts.

The authors compared a microbiota wipeout as something similar to an injury.

“A casual exerciser with a minor injury wouldn’t be affected much. But on a world-class athlete, a small setback can be much more magnified,” said Monica McNamara, the lead author of the study.

Even though the study was on mice models, the researchers believe their findings may have implications for humans.

“Though we are studying mice, their physiology is very similar to humans. The more we learn from them, the better our chances of improving our own health,” Garland said.

“We would hypothesize that antibiotic treatment may have adverse effects on exercise performance, at least in elite athletes,” he told The Epoch Times in an email.

Currently, there have been many studies on the beneficial impact of exercise on microbiota, but very few studies have examined the reverse relationship.

One hypothesis on how microbiome may influence voluntary exercise is through its ability to change carbohydrates into chemicals that travel in the body and take part in certain metabolic processes.

“Metabolic end products from bacteria in the gut can be reabsorbed and used as fuel,” Garland said. “Fewer good bacteria means less available fuel.”

Moreover, microbiome impacts on behavior are believed to also have implications on motivation, suggesting that the gut microbiome plays a role in rewards circuits.

Metabolites produced by the microbiota are able to interact with cells and neurons in the reward pathway, though their function has remained unclear.

Moving forward, the researchers would like to identify the beneficial bacteria responsible for increased athletic performance.

“If we can pinpoint the right microbes, there exists the possibility of using them as a therapeutic to help average people exercise more,” Garland said, with some of the university’s ongoing studies aiming to shed more light in this direction.

Microbiota composition can be improved with healthy eating. Garland recommended maintaining a balanced diet and exercise to promote overall health.

“We do know from previous studies that the western diet, high in fat and sugar, can have a negative effect on biodiversity in your gut and likely, by extension, on athletic ability and possibly even on motivation to exercise,” he said.