So much for the “weaker” sex.

As House Minority Leader Nancy Pelosi proved by giving a record-setting eight-hour speech (at age 77, while standing in four-inch heels) on Wednesday, women are well-suited to endure discomfort and push through muscle fatigue – sometimes even better than men.

The Democratic representative got a shoutout from former Texas Senator Wendy Davis, who literally stood up for women’s rights in 2013 by donning pink Mizuno running sneakers and delivering a blistering 11-hour filibuster on her feet to block the passage of a bill that would restrict abortions across the state.

Now, these strong women do workout when they’re not working. Pelosi reportedly takes a 45-minute power walk along the Potomac River every morning, and Davis is a regular runner and cyclist.

But a growing body of research also suggests that females are biologically conditioned to go the distance.

“As a sports medicine physician who has treated many thousands of sports injuries, I am fully confident in saying that women are simply tougher than men when it comes to pain,” Dr. Jordan Metzl at the Hospital for Special Surgery in Manhattan, and a “Runner’s World” contributor, told Moneyish. “Men say, ‘This hurts me, and I’m going to stop,’ while women say, ‘I’m going to keep going and make these 20 miles.’

“I don’t know why, exactly,” he continued, “but I’d theorize that from an evolutionary point of view, women adapted to be able to withstand the pain of childbirth.”

Also read: As of today, the United States has Senate has more women than ever before

A University of British Columbia study released last summer also suggested that women have greater muscular endurance than men. After tasking nine women and eight men with completing exercises similar to calf raises, the men started out faster and more powerfully than the women at first — but they tired out faster than the females did.

This was a small study isolating just one muscle group, so more research is needed before we can crown women the all-around endurance queens. But study author and professor Brian Dalton told the Independent that, “Women can outlast men by a wide margin. We know from previous research that for events like ultra-trail running, males may complete them faster, but females are considerably less tired by the end.”

(andresr/iStock)

This stamina could be because women’s bodies carry more fat, while men pack on more muscle – and being more muscular doesn’t guarantee greater endurance. The body converts carbohydrates to glycogen, which it uses as fuel in endurance events like distance running. But women appear to burn more fat and less carbohydrates initially than men do — so one theory suggests that women can draw on greater carb reserves later during an endurance event than men, who use theirs up more quickly.  Estrogen may also protect women’s muscles from exercise-induced damage. And a 2001 article found that women fatigued more slowly than men did because they had better blood flow through their muscles.

Women also win the ultimate endurance test: Longevity. American females outlive males by about five years on average. Women live longer than men almost anywhere in the world, in fact, and a recent study finds that infant girls survive harsh conditions better than baby boys. It’s believed that female hormones such as estrogen (which protects women from premature heart disease) and the female body’s resiliency (to handle pregnancy and breastfeeding) also boosts long life in women.

To be sure, men have the benefit of greater muscle mass, lower resting heart rate and higher oxygen intake, which contributes to their superior strength in many feats. For all of women’s endurance strength, the average male still finishes a marathon (26.2 miles) in four hours and 29 minutes, for example, compared to the average female finishing half an hour later.

And repeated research has suggested that men have a higher pain tolerance than women. It’s hard to be sure, since reporting pain is so subjective. But a 2012 Stanford review of more than 11,000 medical records found women tend to feel pain more intensely, and their pain ratings on a 1 to 10 scale were a point higher than men’s on average. Women also seek medical attention for pain-related issues more often than men do, and they take more painkillers.

House Minority Leader Nancy Pelosi (D-CA). (Chip Somodevilla/Getty Images)

Dr. David Putrino, an assistant professor in the department of rehabilitation medicine at the Icahn School of Medicine in Mount Sinai, has been studying endurance, pain and fatigue in high performance athletes with Red Bull.

“What we know about pain is that pain is relative,” he told Moneyish. “So people who have higher pain thresholds have experienced an enormous amount of pain at some point in their lives. So in some cases, women have the higher pain threshold because they have experienced childbirth … and then anything else doesn’t seem so bad, relatively speaking.”

But Dr. Putrino has learned that finding fresh vigor in the midst of pain and fatigue is more about mind over matter than it is about being male versus female. “If you are very passionate about something, you can withstand a lot more to make your goal happen,” he said, citing Olympic athletes who perform record-breaking feats through extreme pain. Remember when U.S. gymnast Kerri Strug landed a gold medal-clinching vault on a severely sprained ankle in 1996, or how Slovenian cross-country skier Petra Majdič pushed through four broken ribs and punctured lung to win a bronze medal in 2010?

“So at the very least, what we can say for sure, is that Nancy Pelosi was passionate about standing up and talking about what she believed in,” said Dr. Putrino, “and no amount of pain was going to stop her from standing there for eight hours and getting it all out.”