Before crawling under the covers tonight, should you think twice before putting on your favorite pajamas?
One poll found more than half of Americans sleep au naturel. Studies are mixed on whether what you wear to bed matters. We waded through the research to provide some answers on the supposed benefits of sleeping sans PJs.
… Improve Your Sleep
Feeling overheated makes it harder to get a good night’s rest. Researchers at the University of Amsterdam found increasing skin temperature just 0.4ºC (0.7ºF) was linked with worsened insomnia and increased nighttime waking.
“You do sleep better if you’re cooler,” explains Dr. Daniel Root, a sleep specialist and medical director at Oregon Sleep Associates.
But layers are important to prevent heat loss, so Root suggests having an extra blanket on the bed in case you catch a chill. Performance sleepwear and sheets made of breathable, moisture-wicking fabrics can also help regulate your body temperature.
… Rev up Your Metabolism
Sleeping naked lowers your core temperature, which may help you lose weight. In a small study of overweight men, lower bedtime temperatures were associated with higher levels of brown fat, a healthy fat that burns calories and increases metabolism to raise your body temperature.
“We have known about this relationship for a long time,” says Dr. Chris Winter, a neurologist, sleep specialist and author of “The Sleep Solution.” “Sleeping naked or in cool environments has been shown to positively affect both sleep and metabolism [because] it takes energy to warm a cool body.”
You could get the same result from turning down the thermostat to 65–68ºF as well.
… Boost Your Body Image
If you think you’ll be too focused on the feeling of your thighs rubbing together or the roll of skin on your stomach to drift into dreamland, think again. Researchers found spending time naked led to significant improvements in body image and self-esteem.
“If the first step to getting comfortable with your body is sleeping naked, that’s a great step,” says Dr. Alyse Kelly-Jones of the Novant Health Women’s Sexual Health & Wellness practice.
It might not be practical to binge-watch your favorite crime drama without clothes on, but sleeping naked is totally doable, especially if it makes you feel more comfortable in your own skin.
… Improve Your Relationship
For couples, sleeping naked could increase relationship satisfaction. A survey of more than 1,000 adults found 57% of those who slept naked felt happy in their relationships (compared with 48% who wore pajamas).
“If you and your partner both sleep naked, the skin-to-skin contact will release the feel-good hormone [oxytocin],” says Fran Walfish, PsyD, a Beverly Hills, California-based relationship psychotherapist.
Research shows even non-sexual contact with the skin boosts levels of oxytocin. The hormone, also released during sex, is associated with lower levels of depression, stress and reduced blood pressure.
… Preserve Sperm Quality
In a 2015 study, researchers tracked 501 couples for 12 months to assess links between underwear choice and sperm quality. The data showed men who wore boxers during the day and slept naked had better overall sperm quality and higher fertility than those who chose tighter-fitting underwear, like briefs.
The connection relates to temperature, notes Root. When the testicles are too warm, it’s harder to make good sperm. Sleeping in briefs, he notes, keeps the testicles snug against the body, increasing their temperature. Sleeping naked — or wearing boxers — gives testicles more room to move, thus improving sperm quality.
… Protect Your Vagina
A whopping 70% of women have experienced yeast infections. Crawling into bed in silky underwear or tight-fitting pajama bottoms could increase your risk of yeast infections, according to Kelly-Jones.
“Moisture causes yeast to grow,” she says. “If you’re wearing something that harbors moisture next to your skin, you’ll be more susceptible to a yeast infection.”
If you don’t want to sleep naked, at least shed your panties to allow your vagina to breathe and reduce the risk of getting a yeast infection.
… Lead to Insomnia
Stripping down to avoid overheating could help you get more restful sleep or it could cause you to wake up repeatedly during the night. It all comes down to temperature.
Research found men who slept in cold temperatures spent more time awake and less time in stage 2 sleep, the stage associated with a lower core body temperature. Results were similar in research done on women: Cold stress impaired sleep led to less time spent in stage 3 (slow-wave) sleep, the cycle associated with drifting into a deep sleep.
The takeaway, according to Root: Sleep naked or wear pajamas.
“The most important thing is being comfortable physically and psychologically when you go to bed so wear [or don’t wear] whatever works for you,” he says.
Originally published May 2018, updated with additional reporting
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