How does temperature affect sleep?

When the days are getting warmer, you might want to reach for the AC or fan to help you cool down. Likewise, when the days are becoming colder, and the temperature is dropping quickly, there’s nothing nicer than snuggling up in bed under a warm doona.

But did you know that the temperature of both your body and your surroundings can affect the quality of rest you get each night? 

Sleep is critical to your health and wellbeing, which means it's important to get the conditions right so you can sleep well and awaken refreshed.

What happens to your body temperature while you sleep?

Sleep consists of several stages¹, with the first being where you transition from waking and into light sleep. During the following stages, your body's core temperature gradually drops to reach the state of deep sleep. However, if your core temperature is too high, your brain can’t clearly differentiate waking and sleep, which directly affects how well you rest.

The surrounding temperature can directly affect your core temperature, meaning that how hot or cold your room is can have a direct influence.

What impact does room temperature have on sleep?

In general, it’s been found that around 18 degrees Celsius is ideal because it suits the cooler temperatures your core experiences during the middle of the night. A low room temperature ensures that your body doesn't warm up and transition too quickly out of the deep sleep stages, thus promoting a more restful night.

Think of your bedroom as a den – the best condition for getting the good rest is when it's dark, cool and quiet!

5 tips to keep the ideal room temperature

You could keep the air-con on all night, however, this would quickly lead to a big energy bill! So how do you keep your room at the optimal temperature without blowing the budget?

1. Turn off the electric blanket before you go to sleep

While it’s tempting to use your electric blanket to make those sheets toasty warm, keeping it on all night will directly raise your core temperature for the entire 7 or so hours. Instead, turn it on for an hour before lights out and then turn it off when you get into bed, so that your body can cool down a bit. If you are instead feeling like the weather is warming up, we have tips on staying cool.

2. Don’t pile on the blankets

While it’s always nice to snuggle up during winter, don’t add too many layers to the point where you’re sweating throughout the night. This can disrupt your sleep as your body struggles to drop its temperature.

3. Turn the heater off but keep the AC on a timer

Having a gas or oil heater on all night as well as a warm doona will not only lead to expensive power bills, but also be counter-productive to a good night’s rest. On the other side, having the AC too cold can also be counter-productive, try to keep the fan or AC running on a timer. Just long enough to let the natural cool night air soothe you to sleep.

4. Do invest in a good mattress

A high-quality mattress often can dissipate your body heat much more effectively than other alternatives, which means that it’s helping your core reach the ideal temperatures for the best sleep.

5. Do keep the window open a crack

During winter, letting the cooler air from outside circulate into your room keeps the air you breathe all night nice and fresh, and can help you lower the temperature to get the best sleep.

Learn how to improve your overall sleep

In a world where it’s all too easy to become sleep deprived, we should aim to get the most out of our sleep so we can wake up to our best selves the next day. 

At ResMed, we’ve created a this eBook available to download right now, called the 8 Ways To Sleep Better Tonight, which explains the 8 best ways to improve your sleep in order to get the best rest out of every night.