June 11, 2019
While pregnant women are often said to be “in a delicate condition,” the truth is, many of them have the mettle and stamina of a top athlete.
The average person can burn up to 4,000 calories—a limit that a group of international scientists considers to be the peak of human performance—before depleting the body’s energy stores. And while extreme distance runners reach maximum performance during high-intensity races, expectant mothers often expend the same amount of energy at a lower intensity over a longer period of time.
The research—published in the journal, Science Advances, on June 5—found that athletes who participated in endurance events such as the 140-day Race Across the USA, were able to maintain their intensity for short periods of time—but when competing in longer, high-intensity events, they weren’t able to replenish the calories they burned throughout the day.
“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 in an interview for a June 6 story. “But if you have to last a week or so, you have to maintain less intensity.”
Longer pushes require lower intensities, but over a short period of time, the human body can successfully exert 4,000 calories on average before hitting the wall. That’s 2.5 times the basal metabolic rate, or amount of calories a body needs to operate while at rest.
The average person won’t reach those limits in a typical workout (except maybe CrossFit, Pontzer told CNN), but pregnant women and extreme athletes cut it close. Weeklong races and nine-month pregnancies similarly push the body to its limits, often burning calories at a rate the body can’t keep up with.
Research contact: @CNN