Extreme endurance running can damage red blood cells and accelerate ageing, according to a study.
Running is one of the most studied forms of exercise with proven benefits across the body, especially of the heart and blood circulation, also indirectly influencing how we age.
Large-scale studies have previously shown that 150 minutes of weekly moderate-intensity running improves one’s healthspan with substantial longevity benefits.
However, recent research indicates that extreme running for longer distances can lead to red blood cell breakdown and potentially cause anaemia.
But the causes and the long-term effects of this phenomenon have remained unclear.
Now, scientists provide proof that ultramarathon athletes’ red blood cells become less flexible after a long race, potentially reducing their ability to efficiently carry oxygen.
They also show signs of inflammation across the body and a decline in molecules that fight off damage to DNA.
“Participating in events like these can cause general inflammation in the body and damage red blood cells,” explained Travis Nemkov, lead author of the study published in the journal Blood Red Cells & Iron.
In the research, scientists assessed red blood cell health before and after athletes participated in the world-class 40km (25 miles)-long Martigny-Combes à Chamonix race, and the Ultra Trail de Mont Blanc race stretching for 171km (106 miles).
Researchers collected blood samples from 23 runners immediately before and after long-distance races and analysed thousands of proteins, lipids, metabolites, and trace elements in their plasma and red blood cells.
Runners’ red blood cells consistently showed evidence of damage, scientists say.
They found evidence of molecule-scale changes likely from inflammation across the body.
These patterns of changes seen in athletes after 40 km races were amplified in those who ran the more trying 171 km races, and can accelerate ageing, researchers say.
As the length of a run increases, scientists say athletes can expect to lose more blood cells and accumulate more damage.
“At some point between marathon and ultra-marathon distances, the damage really starts to take hold,” Dr Nemkov said.
“We don’t know how long it takes for the body to repair that damage, if that damage has a long-term impact, and whether that impact is good or bad,” he added.
Scientists hope further studies can help develop strategies to improve athletic performance or reduce the potential negative impacts of endurance exercises.
Future research into ultramarathon runners can also help improve the shelf life of stored blood, researchers say.
“This study shows that extreme endurance exercise pushes red blood cells toward accelerated ageing through mechanisms that mirror what we observe during blood storage,” said Angelo D’Alessandro, another author of the study from the University of Colorado Anschutz.
