Why 1 French Doctor Says You Should Sleep Naked

Sweating during a workout is one thing, but sweating while you're asleep feels icky. It's also bad for your sleep hygiene, according to French cardiologist and nutritionist Dr. Frédéric Saldmann.

I heard Dr. Saldmann speak on a recent trip to France with skin care brand Vichy Laboratories. The author of several books, including You Are Your Own Best Medicine, offers several science-backed tips for better sleep, focused on creating the perfect conditions for deep snoozing. First, Dr. Saldmann says, make sure your room is completely dark (buy a sleep mask if you must) and cool — he recommends a room temperature of around 64° Fahrenheit. For an even better night's sleep, Dr. Saldmann says you should sleep completely naked.

According to Dr. Saldmann, lowering your skin's temperature increases the depth of your sleep and reduces the number of times you'll wake up in the night. If you cover up with too many layers of pajamas and duvets, you interfere with your body's ability to regulate its temperature. For better sleep, try sleeping completely naked under a light duvet or blanket.

Sleeping naked in a cool room may also have an affect on your metabolism. A sleep study conducted with five men in 2014 found that participants who slept in a mildly cool room (75° Fahrenheit) underneath a sheet saw a 42 percent increase in their brown fat volume. Brown fat (as opposed to white fat, which contributes to obesity) is responsible for burning energy in order to create heat and maintain body temperature. According to the study, "The findings suggest that humans may acclimate to cool temperature by increasing brown fat, which in turn may lead to improvements in glucose metabolism."

If sleeping in a room between 64° and 75° Fahrenheit isn't possible, Dr. Saldmann has a few other chilly solutions: "Take a cold shower before going to bed, or place your pillow in the fridge in the morning. Just lowering your body temperature by less than half a degree will help you fall asleep."

Travel and expenses for the author were provided by Vichy Laboratories for the purpose of writing this story.