Exercise is crucial for a long and healthy life; however, recent studies reveal that ultramarathons can significantly accelerate cellular aging in blood. Athletes completing 170 kilometers in mountainous terrain exhibit more age-related damage in their red blood cells compared to those who run shorter distances.

Long-distance running has been associated with health issues, including temporary immune system suppression and anemia. However, the impact on red blood cells, particularly in mountainous environments, is only beginning to be understood.

Angelo D’Alessandro and his team at the University of Colorado examined blood samples from 11 adults, approximately 36 years old, within hours before and after a 40km trail race. They conducted similar analyses on another group of 12 individuals of comparable age participating in a 170-kilometer ultramarathon over the same terrain.

The researchers discovered that participation in either race can lead to increased accumulation of damage in runners’ red blood cells due to reactive oxygen species. These highly reactive molecules are generated when red blood cells need to transport more oxygen throughout the body.

This cellular damage, which occurs naturally with aging, was markedly heightened in ultramarathon runners. D’Alessandro notes, “Anecdotally, the blood after an ultramarathon resembles that of someone who has just suffered a serious injury. Red blood cells accumulate damage, hastening cellular aging.”

Ultramarathon participation appeared to change red blood cells’ shape from disc-like to more spherical at an accelerated rate, a common occurrence as we age. The disc shape is crucial for navigating small blood vessels in the spleen, where aging red blood cells are typically destroyed. “This spherical morphology leads to entrapment in the spleen, resulting in immune cell clearance,” says Travis Nemkov, also from the University of Colorado Anschutz.

This damage likely stems from the inflammatory response triggered by intense exercise, which increases the circulation of red blood cells.

Additionally, ultramarathon runners experienced approximately 10% fewer red blood cells following the race. While this minor reduction isn’t indicative of a health issue or anemia, it suggests the body can probably recover swiftly from this change, according to Nemkov.

Current research efforts focus on analyzing ultramarathon runners’ red blood cells the day following a race to further comprehend the duration of these effects. Future studies aim to explore if these changes impact runners’ performance. Nemkov emphasizes, “This could reveal insights into the signals of damage that might enhance the body’s resilience to endurance running or indicate potential detriments.”