Antibiotics wreak havoc on athletic performance

Other studies have examined how exercise influences the microbiome, but this study is one of the few to examine the converse: how gut bacteria also influence voluntary exercise behavior. Voluntary exercise involves both motivation and athleticism.

The researchers’ methods and results are now detailed in the journal Behavioral processes.

“We believed that an animal’s collection of gut bacteria, its microbiome, would influence digestive processes and muscle function, as well as motivation for various behaviors, including exercise,” said Theodore Garland, UCR evolutionary physiologist in whose laboratory the study was conducted. “Our study reinforces this belief.”

Researchers confirmed through stool samples that after ten days of antibiotics, gut bacteria were reduced in two groups of mice: some bred for high levels of running, and others not.

Neither group of mice showed any sign of sickness behavior as a result of antibiotic treatment. So when cycling was reduced by 21 percent in the athletic mice, researchers were confident that damage to the microbiome was responsible. Furthermore, the high runner mice did not recover their running behavior even 12 days after antibiotic treatment was stopped.

The behavior of the normal mice was not significantly affected during or after treatment.

“A normal athlete with a minor injury wouldn’t suffer much. But for a world-class athlete, a small setback can be much bigger,” says Monica McNamara, PhD candidate in evolutionary biology at UCR and first author of the paper . “That’s why we wanted to compare the two types of mice.” Disabling the normal gut microbiome can be compared to an injury.

One way the microbiome may influence exercise in mice or humans is through its ability to convert carbohydrates into chemicals that travel through the body and affect muscle performance.

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

In the future, the researchers want to identify the specific bacteria responsible for increased athletic performance. “If we can identify the right microbes, there is the potential to use them as a therapeutic agent to help average people exercise more,” Garland said.

Lack of exercise is known to be a major risk factor for aspects of mental health, including depression, as well as physical health, including metabolic syndrome, diabetes, obesity, cardiovascular disease, cancer and osteoporosis. Many in the public health community would like to promote physical activity, but few have found ways to do so successfully.

“Although we study mice, their physiology is very similar to that of humans. The more we learn from them, the greater our chances of improving our own health,” Garland said.

Certain foods can also increase desirable gut bacteria. As research on “probiotics” develops, Garland recommends that those interested in promoting overall health follow a balanced diet in addition to regular exercise.

“We know from previous studies that the Western diet, which is high in fat and sugar, can have a negative effect on the biodiversity in your gut and probably, by extension, on athletic ability and possibly even motivation to exercise. Garland said.