You can wear any old T-shirt and sweats to bed. But if you’re looking to fill your drawer with pajamas that are designed to keep you cool, you’ll want to invest in sleepwear that has a couple key qualities.
It’s made from breathable or sweat-wicking fabric
All of our experts agree that cotton is one of the best fabrics to look for because it’s known for its breathability, meaning air can easily flow through the fabric. “It can help keep the body cool and works well to absorb sweat in warmer temperatures,” Fatima Fahs, MD, FAAD, a board-certified dermatologist in Michigan and the founder of Dermy Doc Box, tells SELF.
Other fabrics our experts recommend include linen, bamboo, eucalyptus (a.k.a. Tencel), silk, and viscose (or material made from plant fibers, usually wood pulp). All are a loose enough weave to allow air through to the body and either absorb or wick away moisture from the skin, so you won’t wake up in a pool of your own sweat.
Clothes using synthetic materials, like polyester and nylon, can be appealing because they’re cheaper, but these fabrics “tend to trap heat and moisture on the skin, making it uncomfortable and itchy,” Dr. Fahs says. They can also exacerbate conditions like eczema and psoriasis.
Lastly, any fabric with a dense weave that doesn’t allow for breathability is a no-go, so Dr. Moustafa recommends steering clear of wool or spandex (no matter how comfy your Lulu leggings are for workouts).
It has a loose fit
Next to picking the right fabric, the best thing you can do is choose loose-fitting pajamas: This is because too-tight clothes trap in sweat and block the body’s built-in climate control system.
Our skin maintains a healthy (and comfortable) temperature through a process called evaporative cooling, says Dr. Moustafa. “When we get too hot, our eccrine glands that cover our skin bring water and salt to the surface of the skin as ‘sweat,’” she says. When air reaches the skin and dries (or evaporates) this moisture, energy is released in the form of heat and your body’s temp comes back down.
Wetness plus heat is also a recipe for yeast and bacteria growth, so sleeping in skin-tight leggings or bike shorts could lead to body acne, yeast infections, or bacterial vaginosis.