Think running a marathon is just tough on your legs? Think again — your brain’s running the race too!

A fascinating new study dropped a brainy truth bomb: running a marathon might temporarily rewire your brain. This  26.2 miles of sweat and willpower doesn’t just wear down your muscles — they actually reduce the myelin in your brain.

Hold up — what’s myelin?
It’s the protective coating that wraps around your brain’s nerve fibers — kind of like the insulation on electrical wires. It’s crucial for motor coordination, quick thinking, and emotional stability. Basically, your brain’s smooth operator.

The study (published in Nature Metabolism) used MRI scans to peek into the brains of marathon runners before and after the race. The shocking find? A noticeable drop in myelin content right after the event.

Before you freak out — this isn’t permanent damage. Myelin levels bounced back to normal within about two months. Phew.

But here’s the wild part: animal research suggests the brain might actually burn myelin as a backup energy source during extreme stress. Translation? Your brain is so desperate to keep you going at mile 22, it starts using its own insulation as fuel.

Let that sink in:
– Your brain is sacrificing part of itself to get you across the finish line.
– And we wonder why post-race fatigue hits so hard.
– Why recovery isn’t a luxury — it’s a necessity.

Rest isn’t just for sore quads — it’s for your brain and nerves too!
So if you’re pushing your limits — in sport, work, or life — give your brain the downtime it deserves. It’s not just self-care, it’s science.

✨ Your brain works harder than you think.
Let it rebuild.
Then go crush your next goal — smarter and stronger.

Open access: https://www.nature.com/articles/s42255-025-01244-7