Scientists discover the LIMIT to human endurance

Pregnancy pushes a woman's body to the limits nearly as much as extreme endurance sports, research finds A new study of energy expenditure suggests that everyone has a limit People can only burn calories at 2 and a half times their resting metabolic rate Not even the fastest ultra-runners managed to surpass that limit, they found The body starts to break down its own tissues to make up for the calorie deficit

By Victoria Bell For Mailonline

Published: 14:20 BST, 6 June 2019 | Updated: 11:43 BST, 7 June 2019

93 shares

58

View
comments

All humans have a limit to their endurance as they can only burn calories at two-and-a-half times their resting metabolic rate, a study on energy expenditure has found.

The research suggests that not even the world's fastest ultra-marathoners managed to surpass that limit.

They suggest that their findings define the realm of what's possible for humans and that no matter what the activity - everyone hits the same metabolic limit. 

This is the maximum possible level of exertion that humans can sustain in the long term.

Beyond that threshold of 2.5 times a person's metabolic rate, they found that the body starts to break down its own tissues to make up for the calorie deficit. 

Scroll down for video

All humans have a limit to their endurance as they can only burn calories at two-and-a-half times their resting metabolic rate, a study on energy expenditure has found. The research suggests that not even the world's fastest ultra-marathoners managed to surpass that limit

All humans have a limit to their endurance as they can only burn calories at two-and-a-half times their resting metabolic rate, a study on energy expenditure has found. The research suggests that not even the world's fastest ultra-marathoners managed to surpass that limit

HOW DID THEY MAKE THESE FINDINGS?

They compiled measurements of average energy expenditure and metabolic rate for human endurance events, including marathons, the Tour de France, swimming, arctic trekking, and pregnancy. 

By looking at the data over time and found an L-shaped curve.

The athletes energy started out relatively high and then petered out and flattened out at 2.5 times their basal metabolic rate for the rest of the event.

After analysing urine samples collected during the first and final legs of Race Across the USA they found that after twenty weeks of running back-to-back marathons, the athletes were burning 600 fewer calories a day than expected based on their mileage. 

This suggest that the body can 'downshift' its metabolism to help stay within sustainable levels. 

 

Eating more will not boost your performance because the limit may be down to the digestive tract's ability to break down food, the study claims. 

Co-author Associate Professor of evolutionary anthropology Herman Pontzer at Duke

read more from dailymail.....

PREV Indian police spot glowing UFOs zig-zagging over nuclear power plant - ... trends now
NEXT The UK's most sustainable restaurants are revealed - and it's bad news for KFC ... trends now