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Marathon running is as much a mental challenge as a physical one. However, recent research indicates the brains of marathoners undergo more than just mental fortitude during these grueling races. A new study reveals that during intense endurance exercise, such as completing a 26.2-mile marathon, the brain may temporarily break down its protective insulation to utilize it as an emergency energy reserve.
Emergency Brain Fuel During Marathons
Myelin, a fatty substance, acts like insulation for nerve fibers in the brain and spinal cord, akin to the coating around electrical wires. This crucial substance speeds up and enhances nerve signal transmission, vital for functions ranging from motor skills to sensory perception.
During a marathon, athletes primarily depend on carbohydrates, which convert to glucose, as their principal energy source. When these carbohydrate supplies are depleted, the body resorts to fat reserves, potentially including myelin within the brain, according to the study.
Marathon Runners’ Brains Show Temporary Myelin Reduction
Researchers in Spain conducted a study involving 10 runners (eight men and two women) to investigate this phenomenon. They used MRI scans to examine the brains of participants both before and after a 42.2-kilometer race.
The findings were notable: all runners exhibited a reduction in myelin levels, particularly in brain areas associated with motor coordination, sensory integration, and emotional processing.
Myelin Levels Recover After Marathon
Despite these findings, the study offers reassuring news for marathon enthusiasts. The research demonstrated that the runners’ myelin levels started to recover shortly after the race. Within two months, myelin concentrations returned to pre-race levels, suggesting the reduction is both transient and reversible.
Dr. Pedro Ramos-Cabrer, research professor at CIC biomaGUNE in Spain, stated, “Myelin appears to serve as an energy reservoir when other brain nutrients are exhausted during endurance exercise.”
He added, “Further investigation is necessary to determine the relationship between extreme exercise and myelin levels in the brain. Studies with a larger group of participants are warranted.”
Further Research Needed on Cognitive Impacts
The study authors highlighted that their research did not evaluate whether myelin reduction affected the runners’ cognitive functions or physical capabilities. Therefore, additional research is needed to explore these aspects.
Implications for Neurological Research
This study opens new avenues of inquiry regarding myelin’s role in the brain, not only in healthy individuals but also in those affected by aging or neurological conditions.
Dr. Carlos Matute, professor at the University of the Basque Country, suggested, “Understanding the rapid recovery of myelin in runners could offer valuable insights for developing treatments for demyelinating diseases, such as multiple sclerosis.”
In conditions like multiple sclerosis, permanent myelin loss contributes to significant brain damage and degeneration. Myelin impairment is also a significant factor in amyotrophic lateral sclerosis (ALS). While moderate physical activity benefits brain health, some research indicates that very strenuous exercise might be a risk factor for ALS.
The study’s authors pointed out that intense endurance training could present an added risk for individuals with a genetic predisposition to ALS due to its potential to degrade myelin. However, they emphasized that there is no immediate cause for alarm and that further research is required to fully understand this relationship.