Ultra-endurance athletes triumph over staggering distances and harsh conditions. But one of their toughest foes may be their own metabolic ceiling.
By scrutinizing a group of top-tier long-haul athletes, scientists have now helped clarify the upper limits of human energy expenditure. The results, published October 20 in Current Biology, suggest that though the spirit may be willing, the body just can’t beat biology.
Biological anthropologist Drew Best and his colleagues studied a group of 14 elite, highly trained and mostly full-time athletes over the course of a year. The athletes in the study “provide a natural experiment,” says Best, of the Massachusetts College of Liberal Arts in North Adams.