“If we can confirm the presence of a similar pathway in humans, it could provide an effective way to boost people’s exercise levels to improve public health more generally,” said an assistant in microbiology. said senior author Christoph Theis, Professor Ph.D. in Pain Medicine.
Thies and colleagues set up the study to search broadly for factors that determine exercise performance. They recorded genome sequences, gut bacterial species, bloodstream metabolites and other data for the genetically diverse mice. They then measured the amount of daily voluntary cycles the animals ran, as well as their endurance.
The researchers analyzed these data using machine learning, looking for characteristics of the mice that could best explain inter-individual differences in the animals’ running performance. They were surprised to find that genetics appeared to account for only a small portion of these performance differences – while differences in gut bacterial populations appeared to be significantly more important. In fact, they observed that giving the mice broad-spectrum antibiotics to rid them of their gut bacteria nearly halved the mice’s running performance.
Can gut bacteria enhance exercise performance?
Ultimately, in a years-long process of scientific detective work involving more than a dozen different laboratories at Penn and elsewhere, researchers found that two bacterial species were closely associated with improved performance, eubacterium rectal And coprococcus euactus, produce metabolites known as fatty acid amides (FAAs). The latter stimulates receptors called CB1 endocannabinoid receptors on gut-embedded sensory nerves, which connect to the brain via the spinal cord. Stimulation of these CB1 receptor-studded nerves causes an increase in levels of the neurotransmitter dopamine during exercise in a brain region called the ventral striatum.
The striatum is an important node in the brain’s reward and motivation networks. The researchers concluded that excess dopamine in this area during exercise enhances performance by strengthening the desire to exercise.
Co-author of the study, J. Nicholas Betley, Ph.D. An associate professor of biology at the University of Pennsylvania School of Arts and Sciences. “This line of research could develop into a whole new branch of exercise physiology.”
The findings open several new avenues of scientific inquiry. For example, there was evidence from experiments that better-performing rats experienced a more intense ‘runner’s high’ – in this case measured by a decrease in pain sensitivity – indicating that this well-known phenomenon is also at least in part. Less partially controlled by the gut. bacteria. The team is now planning further studies to confirm the existence of this gut-to-brain pathway in humans.
In addition to offering ordinary people cheap, safe, diet-based ways to get running and optimize performance for elite athletes, he said, discovering this route could lead to easier ways to modulate motivation and mood in conditions such as addiction and depression. can also be found.