Running extreme distances may strain more than just muscles and joints. New research suggests ultramarathons can alter red blood cells in ways that make them less flexible and more prone to breakdown, ...

Scientists have discovered that red blood cells act as hidden glucose sponges in low-oxygen conditions, explaining why people ...

After a long trail race, some of your red blood cells may not bend the way they should. That matters because red blood cells have a tight job description.

Learn more about the impact ultramarathon running has on red blood cells and how it may do more harm than good for the body.

Extreme endurance running damages red blood cells in ways that may affect their ability to function properly, according to a ...

Extreme endurance training is often seen as a sign of strong physical fitness. However, new research indicates that very long-distance runs may have negative effects on the body.

Ultramarathons might push red blood cells past their limits—accelerating their aging in the process.

By Dennis Thompson HealthDay ReporterTHURSDAY, Feb. 19, 2026 (HealthDay News) — Ultra-marathon runners must be incredibly fit to endure races that can extend more than 100 miles, but their bodies pay ...

Researchers collected blood from 23 runners right before and right after two endurance races: a 40-kilometre mountain race and the 171-kilometre Ultra Trail du Mont Blanc. They then analyzed thousands ...