Exercise May Improve Health By Increasing Gut Bacteria Diversity

Bacteria often gets an unfair reputation, but there are many beneficial bacterial cells in the body that play important roles in physiology. Growing evidence shows greater gut microbiota diversity is related to better health. This research suggests that cardiorespiratory fitness is a greater predictor of that diversity than general physical activity or body fat percentage.

Cardiorespiratory fitness can be improved with high intensity exercises, and it may support health through beneficial changes in presence, activity, and clustering of gut microbes; exercise induced improvements often correspond with central and peripheral adaptations.

Wider diversity in gut microbiota tends to coincide with higher cardiorespiratory fitness, but it was unclear whether this was attributed to physical activities or body fat percentage. As cancer treatment is known to trigger physiological changes detrimental to cardio-metabolic health this research was conducted on cancer survivors; 37 non-metastatic breast cancer survivors who had completed treatment for at least one year were enrolled in this study.

Examination of gut microbiota via faecal swipes, graded exercise testing to estimate peak cardiorespiratory fitness, and assessments of total energy expenditure were conducted on all participants. Results showed those with higher cardiorespiratory fitness had greater gut microbiota diversity; further analyses showed cardiorespiratory fitness accounted for nearly a quarter of the variances in species richness and evenness independent of body fat percentage.

Findings offer new insight into relationships between cardiorespiratory fitness and gut microbiota diversity, but given the cross sectional nature of this study the data is correlative in nature. Findings are limited to women with a history of breast cancer who tended to exhibit low cardiorespiratory fitness and other health problems; results may not be generalizable to other groups.

The team is pursuing additional studies to determine how variation in exercise intensity may influence gut microbiota diversity under controlled feeding conditions to examine how exercise may affect functional outcomes of gut microbiota; and to study how exercise prescriptions may be optimized to enhance health outcomes among clinical populations.