A recent study published in Nature Metabolism has shed light on the surprising role of myelin in energy production in the brains of marathon runners. The research, led by Carlos Matute from the University of the Basque Country in Spain, explored how participating in marathons affects the levels of myelin, a fatty substance that insulates nerve cells.

The study involved scanning the brains of ten long-distance runners before and after they completed marathons. The results revealed a temporary decrease in myelin levels in brain regions associated with motor control, sensory perception, and emotional processing immediately after the races. However, these levels returned to normal within two months.

While the concept of myelin serving as an energy source for the brain is not entirely new, this study provided novel insights into its potential role during intense physical exertion. Matute, who is both a marathon runner and a neuroscientist, proposed that myelin lipids could contribute to brain energy metabolism under specific conditions, suggesting a strategic use of this substance by the brain when other energy sources are depleted.

Despite the temporary reduction in myelin post-marathon, the study found no significant impact on cognitive function. Matute and his team are further investigating whether this decrease has any short-term effects on brain function. Mustapha Bouhrara from the US National Institutes of Health also noted that the process of myelin repair following a race could be beneficial in enhancing the brain’s metabolic functions.

The inspiration for this study came from Matute’s personal experience as a marathon runner, having completed 18 marathons. Observing the resilience of the human brain during such demanding physical activities led him to question the potential role of myelin in sustaining brain function during periods of heightened energy demand.

By utilizing magnetic resonance imaging (MRI) to analyze the brains of the participants, the researchers observed a clear reduction in myelin levels in specific brain regions associated with the challenges faced during a marathon. The subsequent recovery and “remyelination” process within weeks further support the notion of myelin adaptation to meet the brain’s energy requirements during strenuous activities.

Overall, this study provides valuable insights into the dynamic relationship between myelin, energy metabolism, and physical endurance. The findings open new avenues for understanding how the brain adapts to extreme exertion and the potential implications for cognitive function and overall brain health in marathon runners.