Pregnancy is harder than marathons, science shows

In a groundbreaking 2019 study published in "Science Advances", a scientific journal published by the American Association for the Advancement of Science (AAAS), evolutionary anthropologist Herman Pontzer of Duke University compared the metabolic strain of pregnancy to some of the world's most extreme endurance feats like the Tour de France or a gruelling ultramarathon. The result? Pregnancy outlasts and outpaces them all.

Pontzer's research found that pregnancy demands approximately 2.2 times a person's basal metabolic rate (BMR), which is the energy required to keep the body functioning at rest. That's nearly double the usual energy output, sustained not for a few hours or even days, but for nine continuous months!

In comparison, elite endurance events such as the Tour de France (a physically demanding cycling event of global repute) push the body to about 4.9 times BMR, but only for a few weeks.

Pregnancy, in contrast, offers no such break. It's a continuous, slow-burning effort that reshapes a woman's physiology from the cardiovascular system, kidney function, hormonal balance, to the immune system, supporting the development of a new human being.

So, the next time someone shrugs off pregnancy as simply "part of life", remember that behind every pregnancy is a body working overtime, nonstop, doing what science now confirms is one of the most sustained feats of human endurance ever recorded.