You can have too much of a good thing when it comes to working out
REUTERS/Lucy Nicholson
While exercise is important for a long and healthy life, ultramarathons can accelerate the aging of the cells in our blood. Athletes who ran 170 kilometers over mountainous terrain accumulated more age-related damage to their red blood cells than those who completed a shorter distance.
Long-distance running has previously been linked to health problems, such as temporary suppression of the immune system and anaemia. But we only now have an understanding of what it does to red blood cells – which transport oxygen around the body – especially when it is done outside in mountainous terrain.
Angelo D’Alessandro of the University of Colorado Anschutz and his colleagues analyzed blood samples from 11 adults aged 36 years on average within a few hours before and after they ran a 40 kilometer trail race. They did the same for a separate group of 12 people of roughly the same age who competed in a 170 kilometer long ultramarathon over similar terrain.
The researchers found that competing in both races appeared to cause the runners’ red blood cells to accumulate more damage from molecules known as reactive oxygen species, which are produced at higher levels when these cells need to deliver more oxygen around the body.
But such damage, which naturally accumulates as red blood cells age, was significantly higher in the ultramarathoners. “Anecdotally, the blood after an ultramarathon looks like the blood of someone who has just been hit by a car,” says D’Alessandro. “The red blood cells accumulate damage and age.”
Running the ultramarathon, but not the shorter race, also seemed to cause their red blood cells to change more quickly from a disc shape to a more spherical one, which is usually seen as they age. The disc shape allows them to bend and squeeze through tiny blood vessels in the spleen, where old red blood cells are destroyed. “This spherical shape means they get stuck in the spleen and are eaten up by immune cells,” says team member Travis Nemkov, also at the University of Colorado Anschutz.
This damage is probably due to exercise increasing inflammation and particularly strenuous activity that pushes red blood cells around the body more forcefully, he says.
Also, only the ultramarathoners experienced a drop of about 10 percent in their red blood cell count after the race, but this is not necessarily a problem for their health. This change is too small to cause anemia, and the body can probably quickly recover from it, says Nemkov.
The researchers are now studying the red blood cells of ultramarathon runners a day after they finish a race, to better understand how long these effects last. They also want future work to investigate whether these changes affect the runners’ performance. “This could just be how the injury signals appear to make the body more resistant to endurance running, or it could have a negative impact,” says Nemkov.
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