New studies on female athletes are opening up a world of performance advice.

Why it matters: Sports research has ignored female athletes for decades, but studying women has recently led to breakthroughs for everyone.

Quick updates before we dive in:

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Now onto today’s topic …

In leading academic journals between 2014 and 2020, just 6 percent of studies were conducted exclusively with women. The assumption was that women were basically just small men.

“When we don’t study women and men in similar proportions, it means that our understanding of sports science is weighted heavily towards men and male bodies. It can distort our understanding of what’s considered ‘normal’ physiology because we don’t have a representative sample. We end up making assumptions about exercise and fitness and how bodies are supposed to adapt and perform based on a partial picture of the human population.”

That’s according to Christine Yu, sports and health journalist and author of Up To Speed, an exceedingly well-researched book about the new science of female fitness and physiology.

The result is that active women often struggle with unique conditions but leave the doctor’s office hopeless and without answers.

But recently, studies on female athletes are ramping up. And these studies have been revelatory for everyone.

For example, here’s a cool crossover: When studying female athletes, researchers were surprised to discover that the same behaviors that cause bone and hormonal issues in active women were doing the same in men, tanking their testosterone.

Today we’re six lessons from this new science.

1. Check your fifth vital sign

In short

Menstrual pain and abnormal cycles are red flags for women. So is low sex drive for men.

The details:

Yu spoke with professional female athletes who experienced irregular menstrual cycles, a common condition. One 20-something athlete missed her period for seven years straight. Her trainers thought this was normal.

“What’s shocking to me is that we don’t teach girls and women about these deeper and larger connections between the cycle, our overall health, and how it can influence exercise and performance. It’s only in recent years that we’ve started talking about the menstrual cycle and period symptoms within the context of athletics and even still, it’s largely a taboo topic,” Yu said.

The surge of hormones from a monthly period is super healthy. Without it, women are at greater risk for stress fractures and early-onset osteoporosis.

One study followed a small group of young elite runners and found that those who didn’t menstruate spent more days injured and ran less total mileage compared to their counterparts with a normal cycle.

This is **critical** because building strong bones today leads to fewer issues in old age. Hip fractures are one of the most significant causes of death among seniors.

Doctors now realize that the menstrual cycle is as important a vital sign as heart rate or blood pressure. They call it the fifth vital sign. Here are some red flags for active women:

• You haven’t had a period in more than three months.
• Your periods are irregular.
• Your workouts are painful during your period.

Yu discovered that irregularities could often be a sign of serious conditions. For example, tennis pro Danielle Collins suffered regular period pain so severe that she was forced to pull out of competitions. It was endometriosis.

In active men, low sex drive can signify hormonal problems like low testosterone and underlying issues around exercise or chronic disease.

Sometimes these issues have a simple fix. See below. And if that doesn’t work, consider talking to your doctor.

2. Eat enough

In short

Undereating is common among female and male athletes, and it hurts performance and health.

The details

“Women are subject to so much pressure to look a certain way—generally, thin and lean but not too muscular,” said Yu. “To achieve a certain aesthetic, women often start to restrict food or certain food groups like carbs or train more. But if you don’t feed your body consistently, it’s counterproductive to an active lifestyle.”

The figures on undereating are all over the place. None look great. For example, one study of D-II college female athletes found 25% had disordered eating, 26% had menstrual dysfunction, and 10% had low bone mineral density.

The figures grow for both men and women in sports where endurance, appearance, or weight classes are important. For example, wrestling, rowing, gymnastics, track, cycling, and others.

• In those sports, as many as a third of male and two-thirds of female athletes exhibited signs of eating disorders.

Take the Olympic women’s rowing team for New Zealand. The team long believed  “lean and fast” led to medals. The idea was that keeping calories low created lighter athletes and faster row times.

The problem: The team wasn’t winning.

Then a new senior performance nutritionist analyzed the team’s data and had them eat more. She also pushed the team’s coaches to change their behavior and language around food.

The result: The team won four medals. Four.

How to find “enough”

Your body requires anywhere from 1500 to 2000 calories a day just for essential functions like breathing and regulating your body temperature.

If you want to do more than exist—like, say, dominate everyone at the Olympics or your next local 10K—you’ll need to eat more than a baseline amount of food.

And beyond improving fitness, eating enough promotes cardiovascular health, bone health, immunity, gut health, mental health, recovery, and injury prevention.

“In particular, women’s bodies appear to need a steady supply of carbohydrates, which may explain why women tend to perform worse while on a low-carb diet or when fasting,” said Yu.

Look for signs that you’re undereating:

• For women: you haven’t had a period in a few months.
• For men: low sex drive. Research shows undereating while being highly active leads to lower testosterone levels.

For women, eating enough often promotes menstrual and hormonal health.

There’s likely no “perfect” amount of food. But a general rule is to eat as much as possible until you begin to gain unwanted weight.

An important tip: If you’re currently undereating, don’t just start pounding food. That big jump in food can often lead to fat gain (this is something Layne Norton, PhD, has explained in depth.)

Do this:

1. Determine how much you’re eating, then slowly ramp up your calories. Add, say, 50 more calories every day for one week. Weigh yourself along the way.
2. Next week add 50 more every day for a week. Continue weighing yourself.
3. Continue that process until you begin to see your weight creep up across the week. Note that having your weight jump up and down day-to-day is totally normal. You’re looking for trends.

3. Alter your exercise to age gracefully

In short

Different phases of life may benefit from different kinds of exercise.

The details

For women, “During the menopause transition, your fitness can feel like it falls off a cliff and the body doesn’t respond to training the same way it did in your twenties and thirties. It’s not in your head,” Yu said. “Your body might need a different stimulus, like lifting heavier weights or incorporating some high-intensity sessions.”

Advice for men and women over 45

We recently spoke with Stu Phillips, PhD, one of the world’s foremost researchers on exercise, nutrition, and aging. He told us, “I am convinced that as we age, aerobic capacity begins to take a back seat to strength as an important predictor of morbidity and mortality risk!”

• Women, as long as you move well, consider doing a variation of the classic 5x5 strength program. You could do the standard version or swap in variations of exercise that feel best to you.
• Men, lifting weights after 45 may be more important than lifting weights in your younger years.

Advice for men and women under 45

Get enough cardio.

This is particularly important for men, who often count lifting weights faster as “cardio.” Getting true aerobic exercise like rucking or running before age 45 sets you up for better heart health later on.

Why it matters: Statistically speaking, heart disease is most likely to kill you. And it’s often totally preventable by not living like a dipshit.

4. Be versatile

In short

Doing just one sport or exercise has downsides. Do lots of stuff. (Parents, make sure your kids do this, too.)

The details

“51 percent of young female athletes walk away from sport by age 17,” said Yu.

This is often driven by a young athlete choosing one sport and trying to become the best at it (usually because their parents see sports as a ticket to a scholarship).

But for the kid, the sport begins to feel like a crappy job rather than a fun game (which … please remember that sports are games).

A fascinating paper titled “What Makes a Champion? Early Multidisciplinary Practice, Not Early Specialization, Predicts World-Class Performance” reveals the ideal path to becoming a killer athlete. Its lessons don’t just apply to young adults.

The researchers discovered that world-class athletes:

• Started their primary sport later in life
• Played multiple sports
• Stayed active in a variety of ways
• Initially progressed more slowly than their peers

For example, Steph Curry played baseball, football, and soccer. Alex Morgan did gymnastics until she joined club soccer at 14. (Note: There are, obviously, athletes who specialized early in life and became champions. Like Tiger Woods. But, on balance, most great athletes did not specialize … David Epstein’s book Range covers this more.)

Why it matters

The worst thing is not exercising. But the second worst thing is doing the same exercise over and over and over.

Doing a bunch of different types of exercises and activities makes you more resilient, less likely to experience injuries, and improves aging. It also allows you to jump in on any fun activity or sport that comes your way.

5. Use better gear

In short

A new wave of gear companies are researching what makes gear better for women. The upshot: It’s helped them design better gear for men as well.

The details

It wasn’t just scientists who assumed women were just small men. It was also brands that created gear. Yu refers to this as the “shrink it and pink it” phenomenon.

“It wasn’t until 2019, in advance of the Women’s World Cup, that Nike unveiled soccer uniforms specifically designed for women...The jersey has a longer sleeve to minimize exposure of the upper arm. The neckline is a cross between a crew and a V-neck so athletes can easily pull it over a ponytail,” Yu writes in her book.

These might seem like minuscule tweaks, but Yu cites serious stories from athletes who were hospitalized from an ill-fitting bike saddle, suffered pain from a maternity sports bra gone wrong, or peeled off shoes that left feet blistered and toenails black.

When brands poke their heads out to experiment with clothing and gear that works for women, it helps them see the variety of body types and preferences in the market.

The takeaway

Find gear that works for your body type. Women, know that this may take a bit more effort.

Here are some brands picked by Yu and 2% that think deeply about women’s products:

• Oiselle makes women’s-specific shorts, running capris, and tops
• Brooks revolutionized sports bras (“They’re a company that has been very intentional about studying breast biomechanics during the design and development process,” Yu says)
• Kuhl and Alpine Parrot make great hiking pants for women
• Momentus, a sponsor of 2%, offers a performance supplement line for women. It was created in collaboration with Dr. Stacy Sims.
• LIV makes women-specific bikes. Their Avail Ar 3 was rated the best bike for women by Bicycling Magazine.
• GORUCK’s Rucker 4.0 20-liter size is designed with women in mind.

6. Watch more TV (we can’t believe we just said that)

In short

You can push female-focused research forward—for free—by watching more female sports.

The details

Funding is a key reason there are so few studies on female athletes.

“Scientific studies are expensive to coordinate and run. Researchers rely on grants from agencies like the National Institutes of Health, organizations like the NCAA or the NFL, and private companies like Gatorade,” Yu says.

For the uber-passionate, donate to the VOICE IN SPORT Foundation, a nonprofit dedicated to increasing equity in sports science research.

The next best thing you can do is watch women’s sports on TV. Sports television contracts are worth big money. The more viewers, the bigger the contracts, and the more money trickles into sports research.

“Watch the women’s games. Support the women’s game. Read about the women’s game,” Yu said.

Recent reports have discovered that leagues like the NCAA and the NWSL vastly undervalued and underfunded women’s sports. For example, this year’s NCAA Division I women’s basketball national championship was bonkers. LSU clinched their first-ever championship against Iowa’s Caitlin Clark, a record-breaking college junior. There were player rivalries! Unforgettable outfits!

Or there’s the UFC. The women’s division fights are often the best of the cards. Just watch Amanda Nunes’ highlight reel.

(And, by the way, go Aces—the first team to bring my hometown of Las Vegas a professional championship.)

Thanks for reading. Have fun, don’t die, be fit no matter who you are.

-Michael

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