A recent study published in the journal Nature Metabolism has found that marathon runners experience a reversible reduction in myelin in their brains during and after a race. The research, conducted by a team of neurologists, neuroradiologists, and biomaterials specialists from Spain, analyzed MRI scans of 10 runners before and after a 42K marathon.
The study reveals that all the runners experienced a decrease in myelin levels in parts of their brains used for motor coordination, sensory integration, and emotion processing. However, the researchers found that the myelin began to rebound shortly after the race and returned to normal levels within two months.
Myelin is a lipid that acts as an electrical insulator for brain cells. The researchers suggest that one of the fat sources burned by runners during long-distance exercise may be myelin itself. Further studies are needed, however, to confirm this theory and understand the underlying mechanisms behind the reversible damage to brain myelin caused by marathon running.
The study’s findings have significant implications for our understanding of brain metabolism and could lead to new insights into the effects of exercise on the brain.
Source: https://medicalxpress.com/news/2025-03-marathon-runners-reversible-reductions-myelin.html