Pregnancy: The Ultimate Endurance Event

Dear Rosies,

Late in a pregnancy, the body runs a furnace day and night. Hunger returns an hour after a meal, and the tiredness settles into the bones by midafternoon. If you've carried a child, you know that feeling from the inside. Science now has a number for it.

Looking for the ceiling

In 2019, a team co-led by evolutionary anthropologist Herman Pontzer of Duke University went looking for the limit of human endurance. They gathered energy data from the most punishing events they could find, including the Tour de France and a footrace across the United States that lasted months.

Over a day or two, an athlete can burn enormous amounts of energy. Over weeks and months, the body settles at a ceiling of about 2.5 times its basal metabolic rate, the energy it spends at rest. For the average person in the study, that came to roughly 4,000 calories a day. When the cross-country runners kept going, their metabolisms slowed to stay under that line.

The team traces the ceiling to the gut. The digestive system can only absorb so much food in a day, which is why the paper calls it an alimentary limit.

Where pregnancy sits

Then the researchers placed pregnancy on the same chart. Pregnant women reached about 2.2 times their basal rate, close to the ceiling the athletes hit. A race ends in days or weeks. A pregnancy builds toward that edge over many months. "If you think about it, it's like the ultimate endurance activity," Pontzer said. The authors note that weight gain in pregnancy may affect the numbers, so read 2.2 as an approximation.

Here's where I stand: a woman growing a child is working at the outer edge of human physiology, and she deserves the care we lavish on athletes. They get recovery days, bodywork, extra food and people who make sure they rest.

Tending the skin that stretches

Through all of it, the skin of the belly and breasts stretches to hold the work. Each evening, warm a palmful of Anoint between your hands and smooth it in long strokes over the belly and up around the breasts. Oil keeps stretching skin supple and calms the dry itch that comes as it grows. After the birth, the same ritual welcomes the body home.

Then put your feet up. Athletes call it recovery.

To your most beautiful, valued, sacred embodiment,
Christine

Check with your midwife or doctor before adding any new product in pregnancy. If itching becomes intense, especially on the palms and soles, call your provider: it can signal a liver condition called cholestasis of pregnancy.

Source: Thurber C. et al., "Extreme events reveal an alimentary limit on sustained maximal human energy expenditure," Science Advances 5, eaaw0341 (2019). doi:10.1126/sciadv.aaw0341