Why it’s Easier to Sleep When You’re Cool

If you’ve ever tried to fall asleep on a hot summer night, you know heat and sleep don’t mix. Your body is clever, and it knows just what it needs to drift into a restful slumber.

The Perfect Temperature for Z’s

A thermostat set between 60 and 67 degrees Fahrenheit (or about 16 to 19 degrees Celsius) is ideal for bedtime, according to sleep.org. The question is: Why does a cool room result in a better snooze?

Why Temperature Matters

Sleep experts explain that decreasing temperatures signal the body to sleep. As you fall into the REM cycle, the brain also takes a rest, allowing the warmth or coolness of your room to control your body’s temperature.

You’ve probably been taught that the body’s normal set point is 98.6 degrees Fahrenheit (or 37 degrees Celsius).

The truth is, your temperature fluctuates—increasing up to two degrees—in a 24-hour period. And so it makes sense that as it begins rising in the morning, you’ll feel a boost in energy. By late afternoon, your temperature slowly drops, eventually signalling the need for sleep at night.

UniSA sleep researcher, Dr. Van den Heuvel, describes the process in detail in a university news story.

He says:

“About one to one and a half hours before falling sleep, the body starts to lose heat from its central core, and that brings on increased feelings of tiredness in normal healthy adults. These physiological changes happen well before going to bed and may be occurring before people realise them.”

How Increased Body Temperature Affects Sleep

Dr. Van den Heuvel notes that people who suffer with insomnia have an increased core body temperature before attempting to fall asleep.

Insomniacs, therefore, have to wait for their temperature to fall before getting any shuteye.

“We’re only talking about a half to one degree, but that small temperature change can result in significant differences in arousal between insomniacs and people without sleeping problems,” the doctor shares.

What You Can Do

Don’t Bundle Up: People who have trouble sleeping should avoid wearing warm clothing to bed and opt for light, breathable fabrics instead.

Think of Your Bedroom as a Cave: Sleep.org suggests viewing your bedroom as a cave; keep it “quiet, cool, and dark for the best chance at getting enough rest,” the organization tells readers.

Take Care of Your Tootsies: Hot water bottles at the foot of your bed—or slipping on socks—will help lower your body temperature by dilating blood vessels more quickly, the sleep experts add.

Pick Up a New Thermostat: Now that you know your body’s daily internal cycle, consider installing a programmable thermostat in your home. Setting the temperature to gradually decrease throughout the late afternoon and evening may help you fall asleep more easily at night.

Treat Yourself to a New Pillow and Add a Fan: Cuddling up with a cooling pillow and adding a fan to your bedroom are simple changes that can make a big difference. Make sure you check out my article on the best cooling pillows for help choosing the right one!

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