A small, cutting-edge study suggests the brain may temporarily convert its own myelin into fuel during extreme endurance events like marathons. This unexpected mechanism could help protect overall brain function when glucose supply drops during intense exercise.
Researchers in Spain followed 10 marathon runners, scanning their brains with MRI before and after the races. They found that 24 to 48 hours after finishing a grueling 42-kilometer run, myelin levels in key brain regions—those governing movement, coordination, sensation, and emotion—decreased noticeably. Importantly, these changes were not permanent. By two weeks post-race, myelin began to recover, and most participants returned to baseline within about two months.
The team describes this as “metabolic myelin plasticity”—the brain recycling myelin as an energy reserve in desperate times. This shifts the traditional view of myelin as solely an insulating layer. Instead, myelin could serve as a temporary energy store that helps the brain maintain essential functions during nutritional stress. The study was led by Pedro Ramos-Cabrer and Alberto Cabrera-Zubizarreta, who argue that brief myelin consumption might help safeguard overall brain performance when needed most.
Past assumptions held that the brain relies primarily on glucose, avoiding fat as an energy source. Yet recent animal studies align with these findings, indicating myelin can act as an emergency fat reserve. Although the sample is small, the results offer a glimpse into the brain’s adaptable energy strategies and echo reports of transient cognitive dips in runners immediately after a marathon, with recovery occurring as the body replenishes.
The work touches on a long arc in human evolution. Regions rich in myelin are prominent in higher brain areas, and this rapid recycling could have supported humans’ endurance and vigilance during strenuous activities. In other words, myelin may both enhance neural efficiency and serve as a short-term energy fallback when endurance is pushed to the limit.
For Thai readers, the study arrives amid a rising interest in marathon culture and long-distance events across Thailand. Understanding brain energy strategies could influence training and recovery practices, as well as spark attention to any potential long-term neurological implications of sustained endurance exercise. As athletes push toward personal bests, this research emphasizes the importance of balanced recovery and nutrition that supports brain health and myelin restoration.
While more research is necessary, these findings encourage athletes to pair high-intensity training with adequate rest and brain-friendly nutrition. A diet that supports neural health and facilitates myelin recovery could help prevent adverse effects on brain function over time. The study lays groundwork for deeper exploration of how brain metabolism and physical performance intersect.