From the Ironman triathlon to the Tour de France, some competitions test the limits of even the toughest endurance athletes.
From the Ironman triathlon to the Tour de France, some competitions test the limits of even the toughest endurance athletes. Now, a new study of energy expenditure during some of the world’s longest, most grueling sporting events suggests that no matter what the activity, everyone hits the same metabolic limit -- a maximum possible level of exertion that humans can sustain in the long term.
When it comes to physical activities lasting days, weeks and months, the researchers found, humans can only burn calories at 2.5 times their resting metabolic rate.
Not even the world’s fastest ultra-marathoners managed to surpass that limit, the researchers found.
“This defines the realm of what’s possible for humans,” said study co-author Herman Pontzer, an associate professor of evolutionary anthropology at Duke University.
Read more at Duke University