New research published in Nature Metabolism found that marathon running can actually lead to a reduction in a crucial substance in your brain known as myelin. Myelin is a fatty substance that insulates nerve fibers in the brain and spinal cord, and aside from making up about 40 percent of the brain’s white matter, it also plays a key role in assisting with motor coordination and sensory regulation. Moreover, other studies have found that lower myelin content in the brain has been linked to cognitive decline. So does that mean marathon runners are at an elevated risk for brain issues?
While marathon running was associated with a decrease in myelin content, researchers say that this is actually a good thing. We explore why they believe that’s the case in today’s blog.
Running And Brain Health
Regular exercise is great for your overall health, and running is one of the most common forms of exercise. Marathon running is one of the ultimate forms of running, and researchers were interested in learning more about the impact 26.2 miles of running has on the brain. For the small study, researchers conducted magnetic resonance imaging (MRI) on 10 runners both 24 and 48 hours before and 24 and 48 hours after a marathon. That’s when they uncovered a substantial reduction in myelin water fraction, which is a good indication of overall myelin content in the brain.
Myelin plays a few vital roles in your brain, including helping to convert glucose to energy for the brain. When stored glucose runs out, which can happen more easily during prolonged high-energy consuming activities like marathon running, researchers hypothesize that your brain turns to myelin lipids for energy. So is the brain actually drawing from essential reserves that could serve to hurt itself in the long run? Researchers actually believe the opposite is true.
That’s because in healthy individuals, myelin tends to regenerate within a couple of weeks or months, and this regenerative myelin can be healthier than the old form. The process is similar to muscle formation, in that muscle fibers actually tear during strength training, and then new fibers are created as the muscle repairs itself, and you are stronger because of it. So while natural myelin depletion as you get older could be a potential cause for concern, a temporary dip and regeneration can serve to help keep your brain strong!
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