How much we benefit from exercise may be down to our gut microbiome AzmanJaka/Getty Images

Your gut microbes may determine how you respond to exercise. That is according to research showing how people with certain microbiomes have better metabolic outcomes after exercise. The discovery opens the door to diabetes treatments that target the microbes in our gut.

Type 2 diabetes is a growing problem internationally. While there is no cure, it can be prevented by early lifestyle interventions, says Aimin Xu at the University of Hong Kong.

“Exercise is the most cost-effective strategy for diabetes prevention,” he says. “However, some people do not respond favourably to exercise.”


To understand why, Xu and his colleagues studied how exercise affected the microbiome and metabolism of 39 men with prediabetes, where blood sugar levels are higher than normal, but not high enough to qualify for a diagnosis of diabetes.

The participants, who had never taken medication for the condition, were randomly assigned either to a sedentary control group, or to a group that undertook a three-month, high-intensity, supervised exercise training course. They were told to maintain their usual diet.

While all participants in the exercise group had similar levels of weight and fat-mass reduction, only 70 per cent had significant improvements in glucose metabolism and insulin sensitivity, Xu found.

An analysis of their gut microbes revealed that the people who saw improvements in glucose metabolism and insulin sensitivity had significantly different microbiomes that were able to generate more molecules called short-chain fatty acids and break down more branched-chain amino acids. the microbiomes of non-responders were more likely to produce compounds that are harmful to metabolism.

Next, the researchers asked the study participants to provide faecal samples, and transplanted the microbes they contained into obese mice. Rodents receiving microbes from people who responded well to exercise went on to develop better insulin resistance and glucose regulation. The rodents receiving microbes from people who hadn’t responded to exercise didn’t see any boost to these processes.

“[Our study] identifies maladaptation of gut microbiota as a “culprit” for those individuals who do not respond to exercise intervention,” says Xu. “This is one of the first interventional randomised control trial studies providing clear evidence of the role of gut microbiota on metabolic health.”

The findings raise the possibility that targeting gut microbiota can maximise the benefit of exercise and could help doctors personalise treatments.

The study only included men. Gut microbiomes can differ depending on sex, so the team plans to undertake similar research into women and older people in the future.

Journal reference: Cell Metabolism, DOI: 10.1016/j.cmet.2019.11.001