Men and Women May Differ in How Fitness Level Is Linked to Gut Microbiome Diversity

Minneapolis-Aerobic fitness may be influenced by microbes in the gut, but men and women appear to show a different connection, according to a first-of-its-kind study. Researchers will present these findings at the 2026 American Physiology Summit in Minneapolis. The Summit is the flagship annual meeting of the American Physiological Society (APS).

Exercise benefits nearly every system in the body: it strengthens the lungs, improves metabolism and helps lower the risk of heart disease and diabetes. Physical activity can also influence the community of bacteria living in the digestive tract, also known as the gut microbiome.

Researchers evaluated male and female volunteers during a cycling test to determine if measures of aerobic fitness were related to the diversity of microbes in the gut. A diverse microbiome containing many different types of bacteria is generally a sign of a healthy gut.

The research team evaluated the volunteers' VO2 max, which measures how effectively the body uses oxygen during intense exercise, and maximal metabolic steady state, which is the exercise intensity a person can sustain for an extended period. A gut microbiome analysis found "alpha diversity, which is the overall abundance and richness of microbes in an individual's microbiome, is highly correlated to fitness parameters in men but does not seem to be related to these parameters in women," said Kristina Binder, a graduate student at the University of Oregon and corresponding author of the study.

"This study is the first to suggest men and women may have differences in how their gut microbiome composition is linked to in their overall health and performance," said Binder. While the reasons for these differences are not yet clear, the findings "may indicate that biological sex could influence gut microbiome adaptations to external stressors such as exercise."

NOTE TO JOURNALISTS: The American Physiology Summit will be held April 23-26, 2026, in Minneapolis. To schedule an interview with the researchers, conference organizers or presenters, or to request the abstract "Relationship Between the Gut Microbiome and Measures of Aerobic Fitness in Humans," contact APS Media Relations or call 301.634.7314. Find more highlights from the meeting in our Newsroom. 

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