Any woman who has ever been pregnant knows that it can take a toll on your body. The strength and energy required to carry another growing and developing human being inside your own while you go about your daily routine can be exhausting. Just as exhausting as running a marathon, it turns out. A new study has proven that being pregnant requires the same level of endurance as one needs to run a marathon or compete in a triathlon.

A new study published in Science Advances looked at the energy expenditure of athletes competing in extreme sporting events such as transcontinental racing and compared it to others "such as long distance trekking and pregnancy," CTV News reports. "Researchers were surprised to find that the maximum energy expenditure among endurance athletes was only slightly higher than the metabolic rate women sustain during pregnancy, which peaks at 2.2 times higher than their resting rate," CTV wrote.

"You can do really intense amounts of work for a day or so," Herman Pontzer, a Duke University researcher who co-led the study, told CNN. "But if you have to last a week or so, you have to maintain less intensity."

The study shows that extreme athletes can exert 4,000 calories on average during a high-intensity workout but it eventually levels out. Athletes participating in these extreme activities, like triathlons or endurance races, burn about 2.5 times their basal metabolic rate. Pregnant women often sustain a basal metabolic burn of about 2.2 times, which is only slightly lower than extreme athletes.

While many mothers weren't surprised by the results of the study, Pontzer told CTV that it does mean that people may be more physically capable than they think they are. “I think we all have the potential—but how do we reach it? With pregnancy, your body takes over and you have no control over it,” he explained. “Every mother who has gone through a pregnancy has experienced that effort themselves.”

Pontzer added that the results of the study “defines the realm of what is possible for humans.”

Being pregnant is no joke and isn't just mentally taxing but physically exhausting as well, and now there is research to prove it.  "If you think about it, [pregnancy] is like the ultimate endurance activity," Pontzer added. We couldn't agree more.

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