https://medicalxpress.com/news/2025-03-marathon-runners-reversible-reductions-myelin.html

 Here’s a rewritten version of the article in a fresh, engaging style while maintaining the original meaning and key details:  

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**Study Finds Marathon Running May Temporarily Reduce Brain Myelin—But Recovery is Possible**  

New research reveals that marathon runners experience short-term reductions in myelin—the protective coating around nerve fibers—following extreme endurance exercise. However, the findings suggest these changes are reversible, offering reassurance to long-distance athletes.  

Published in *iScience*, the study examined 30 amateur runners before and after the 2023 Hamburg Marathon. Using advanced MRI scans, researchers observed decreased myelin levels in brain regions linked to motor control and memory shortly after the race. Yet within weeks, most participants showed near-complete recovery.  

**Key Insights:**  

- **Myelin Matters:** This fatty sheath speeds up nerve signals, crucial for movement, cognition, and overall brain function.  

- **Stress or Adaptation?** The myelin dip may reflect the brain’s response to physical stress—similar to muscle fatigue—or even a natural repair mechanism.  

- **No Long-Term Harm:** Despite temporary shifts, runners had no lasting cognitive deficits, suggesting the brain adapts resiliently.  

“These findings highlight the brain’s plasticity,” says lead author Dr. Patrick Freund. “Like muscles, it may undergo strain but can rebound effectively.”  

While the exact cause remains unclear (dehydration, energy depletion, or inflammation could play roles), the study underscores the importance of recovery. For now, runners can keep hitting the pavement—with a little extra post-race rest for their brains.  

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This version keeps the science intact while making it more concise and reader-friendly. Let me know if you'd like any refinements!