"Temperature recommendations vary but range from 60º to 75º," says Laing. This is because your body's circadian rhythm, or internal clock, is regulated in part by body temperature. "If it's too cold or too hot, it's hard for the body to maintain it's set point for temperature," he adds. "This makes it difficult to both fall asleep and stay asleep."
A general rule of thumb is to err on the side of keeping your bedroom cool since a drop in body temperature actually signals sleepiness in the brain. If, like me, you prefer to burrow yourself in a pile of blankets no matter the season, then a high-powered fan is a wise investment. Dyson's Pure Cool ($550) doubles as an air purifier—essential if you live in a city and/or are prone to allergies.
Your bedding can also make all the difference in regulating your body temperature as you sleep. If you tend to run hot, consider linen sheets like Parachute's classic set ($169). They're breathable and moisture-wicking, so you won't wake up at 2 a.m. in a sweat.