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You can have too much of a good thing when it comes to exercising<\/p>\n
REUTERS\/Lucy Nicholson<\/p>\n<\/p>\n
While exercise is important for a long and healthy life, ultramarathons may accelerate the ageing of cells in our blood<\/a>. Athletes who ran 170 kilometres over mountainous terrain accumulated more age-related damage to their red blood cells than those who completed a shorter distance.<\/p>\n Long-distance running has been linked to health issues before<\/a>, 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 \u2013 which transport oxygen around the body \u2013 particularly when done outside on mountainous terrain.<\/p>\n Angelo D\u2019Alessandro<\/a> at the University of Colorado Anschutz and and his colleagues analysed blood samples from 11 adults aged 36, on average, within a few hours before and after they ran a trail 40-kilometre race. They did the same for a separate group of 12 people of around the same age who competed in a 170-kilometre ultramarathon over similar terrain.<\/p>\n The researchers found that competing in either race seemed to cause the runners\u2019 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.<\/p>\n But such damage, which naturally accumulates as red blood cells age, was substantially higher in the ultramarathon runners. \u201cAnecdotally, the blood after an ultramarathon looks like the blood of somebody who\u2019s just been hit by a car,\u201d says D\u2019Alessandro. \u201cThe red blood cells accumulate damage and become more aged.\u201d<\/p>\n Running the ultramarathon, but not the shorter race, also seemed to cause their red blood cells to shift more rapidly from a disc shape to a more spherical one, which is typically seen when 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. \u201cThis spherical shape means they get stuck in the spleen and eaten up by immune cells,\u201d says team member Travis Nemkov<\/a>, also at University of Colorado Anschutz.<\/p>\n This damage is probably due to exercise increasing inflammation and particularly strenuous activity pushing red blood cells more forcefully around the body, he says.<\/p>\n