Yes, it’s hot. But is it healthy to sleep with the air conditioning on?

Getting a good night’s sleep can be difficult at the best of times, let alone during a heatwave. As cities across the country are subjected to scorching temperatures this summer, many Australians are doing whatever they can to keep cool on hot nights.

But why is it so difficult to fall asleep in the summer? And, on the hottest nights of the season, is it actually a good idea to keep the air conditioning running all night?

Christopher Gordon, professor of sleep health at Woolcock Institute of Medical Research, says sleep and temperature are intricately related because each night our body temperature drops naturally, which helps us fall asleep.

Experts say room temperature can significantly impact your quality of sleep.Credit: iStock

Gordon says body heat escapes through the skin, but if the air temperature is too warm, the heat has nowhere to go, and it’s difficult to cool down.

“It will have an impact on you trying to fall asleep and, importantly, stay asleep,” he says. “You need a cooler ambient room temperature to try to help you facilitate sleep.”

“You’re waking because it’s too hot, and your body’s wanting the opposite.”

On these nights, Gordon says air conditioning is a good tool to control your sleep environment specifically to your needs. “Air conditioning can completely modify the room temperature and make it comfortable and exactly the type of temperature you need for sleeping.”

But what is the best temperature for sleeping? According to Gordon, it’s believed to be between 18 and 20 degrees, which means setting the air conditioner at about 24 degrees. However, he stresses there is no hard and fast rule.

“What we recommend is the room temperature should be cool, but not cold,” he says. “I use the word ‘cool’ because that is better for people to understand as opposed to giving an actual temperature … Everybody perceives temperature differently.”

If you don’t have an air conditioner in the bedroom, a fan is the next best thing to circulate airflow which can assist in cooling the body down.

Sleep Health Foundation chief executive Dr Moira Junge says sleeping with the air conditioner on is a matter of personal preference, though there are other factors that should be considered when doing so, such as the cost and the environmental impact.

“It’s a big drain on energy resources and one’s energy bill and emissions to have air conditioning going all night,” she says.

Sleep Health Foundation chief executive Dr Moira Junge says everyone has different preferences for what temperature they like to sleep in.

For people who might experience respiratory irritation from an air conditioner, Junge says they should be cautious. This means cleaning filters regularly and considering exactly how close they are sleeping to the appliance. However, she says there is no scientific research linking sleeping with the air conditioner on to airway irritation.

According to Junge, other environmental factors in the bedroom, such as noise, light and sense of safety, can also be modified to improve sleep quality without using air conditioning.

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