What are the limits of our possibilities? No one really knows. For a long time researchers have been trying to determine the limits of human endurance, and they’ve finally done it, even going so far as to calculate a number to estimate human endurance. Although endurance varies from person to person, researchers believe there is a value which determines how far people are ready to go to accomplish their goals or persist in a task.
According to the BBC, researchers tested some of the most extreme athletes in the world to determine the limit of human endurance. The new study answers the question of whether there is a limit to our endurance and even detailed what that ultimate limit is.
Researchers at Duke University tested athletes competing in a 140-day, 3,080 mile run across the United State to see how this activity affected their bodies. They also studied cyclists competing in the Tour de France and athletes in other elite events. They measured the athletes’ resting metabolic rate, also known as RMR, which looks at the number of calories the body burns at rest. They calculated these rates before the race, during the race and after the race. The results were published in the journal Science Advances, and they indicate that energy use starts at a high rate and begins falling over time, resulting in 2.5 times their resting metabolic rate.
“You can do really intense stuff for a couple of days,” Duke University’s Herman Pontzer told BBC News, “but if you want to last longer then you have to dial it back.”
The longer the body is pushed to perform and testing a person’s endurance, the closer they approach to the 2.5 times RMR, which scientists believe is the limit of human endurance.
“Every data point, for every event, is all mapped onto this beautifully crisp barrier of human endurance,” Pontzer said. “Nobody we know of has ever pushed through it.”
The reason why 2.5 times RMR is considered the very limit is associated with how we digest nutrients and convert the food we eat into energy. The researchers found that the human body is likely incapable of digesting and going through enough food nutrients to generate a value higher than the 2.5 times RMR in caloric intake on the long run. While the human body is capable of taking advantage and using other energy stores in the beginning, once the energy burns up, the body reaches the limit of human endurance.
According to Pontzer, the findings of this study about the limit of human endurance can help athletes balance their energy use better.
“In the Tour de France, knowing where your ceiling is allows you to pace yourself smartly,” he told BBC News. “Secondly, we’re talking about endurance over days and weeks and months, so it is most applicable to training regimens and thinking whether they fit with the long-term metabolic limits of the body.”