• Ultramarathons may damage red blood cells and accelerate aging Extreme endurance running may quietly age your red blood cells from the inside out. • Running extreme distances may do more than exhaust muscles. • A study published in the American Society of Hematology’s journalBlood Red Cells & Ironreports that ultra-endurance events can injure red blood cells in ways that may interfere with how they function. • Researchers do not yet know how long the damage lasts or what it means for long-term health, but the findings add to growing evidence that very intense exercise may sometimes strain the body rather than strengthen it. • Earlier researchfound that ultramarathon runners often experience a breakdown of healthy red blood cells during races, which can potentially lead to anemia. • However, scientists have not fully understood why this happens.
Article Summaries:
- Summary
A 2026 study published in Blood Red Cells & Iron found that ultramarathon running can damage red blood cells (RBCs), reducing their flexibility and increasing their breakdown. Researchers collected blood from 23 runners before and after two races (40 km and 171 km) and performed comprehensive proteomic, lipidomic, and metabolomic analyses. Results showed mechanical stress from intense blood flow and molecular damage linked to inflammation and oxidative stress. The findings suggest that extreme endurance exercise may accelerate cellular aging and impair oxygen delivery, though the long‑term health implications remain unclear.
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