Endurance Running Triggers Temporary Myelin Use as Brain’s Emergency Fuel, Study Finds
A small pilot study suggests the brain may tap its own energy reserves during intense endurance efforts. Spanish researchers observed changes in brain white matter among marathon runners, hinting at a form of neuroplasticity that could help preserve function under extreme physical stress.
Researchers conducted MRI scans on ten endurance runners (eight men and two women) before and after a 42-kilometer race. The scans showed a measurable drop in myelin, the fat-rich sheath around nerve fibers that facilitates rapid signaling. The decrease was most evident in brain regions responsible for movement, balance, sensory processing, and emotion. Notably, myelin levels began to recover within 24 to 48 hours after the race and largely returned to baseline within two months for the six participants who had follow-up scans.