Rising Temperatures Make Sleep a Challenge—Here's How To Stay Cool and Get Some Rest

Triple digit temperatures have been breaking records across the country in recent weeks and amid such conditions, staying cool is a necessity. Even at night, it can be hard to find relief during a heatwave, making sleeping difficult.

Just this summer, there's been drastically high temperatures across Europe, India, California, Texas, and many other parts of the globe. And because of climate change, these heat waves are happening more often and longer, even extending into the spring and fall months. Also thanks to climate change, night time temperatures are rising even faster than daytime temperatures.

All of which means we're more likely to run into days or even weeks where it can be challenging to sleep. A hot environment can lead to issues with staying asleep throughout the night, and with getting a deep, restful sleep. Over time, poor sleep can move from uncomfortable to dangerous for our wellbeing.

Even though there isn't much we can do about the weather, experts have tips and recommendations for getting the best sleep you can during a heatwave—everything from simple sleep environment adjustments, to changes in your daily routine.

Here's why sleeping amid extreme heat conditions can be so miserable and unhealthy, and some of the solutions that can be adopted to stay cool and comfortable at night.

Cool Environment Leads To Better Sleep

A review article published Thursday in the Journal of Sleep Research traced some of the issues associated with trying to sleep during a heatwave.

"Sleep and temperature regulation are closely related," study author Chiara Baglioni, PhD, faculty of medicine in the department of psychiatry and psychotherapy at the University of Freiburg in Germany, told Health in a statement. "If ambient temperature outside reach[es] levels outside the thermal comfort zone, this interferes with our ability to reduce core body temperature."

Essentially, the body's core temperature cycles in line with what scientists call our sleep-wake rhythm. When it's time to sleep, our bodies naturally become cooler. But when the environment around us is too warm, our core temperature and skin temperature don't get as cool as they should, and we can find it hard to fall or stay asleep.

"Our temperature drops, everything kind of reduces, our metabolism drops, everything drops a little bit when we sleep, and so being extremely hot means that the body has to work extra and systems have to work harder to keep us cooler," Temitayo Oyegbile-Chidi, MD, PhD, associate professor of neurology at the University of California Davis, and the chair of the board of directors of the National Sleep Foundation, told Health. "That's not ideal and this is why we tend to wake up a lot during sleep when it's hot."

And waking up frequently at night because you're hot and sweaty isn't just annoying and uncomfortable—the disruption to normal sleep patterns can be harmful to our health over time.

Poor sleep can lead to a number of health conditions, according to the Centers for Disease Control and Prevention (CDC), including type 2 diabetes, heart disease, obesity, and depression. Being chronically tired can also put us at a greater risk of getting into car crashes or making workplace mistakes, both of which can sometimes lead to injury.

"Sleep difficulty over weeks or months is…not ideal for general health. We know that [with] sleep fragmentation and an inability to consolidate your sleep, you're more likely to end up having medical problems," Dr. Oyegbile-Chidi said. "But even on a day-to-day basis, you can have more irritability and crankiness, an inability to concentrate, you can be hungrier during the day, things like that. So it really affects multiple systems."

Simple Tips To Stay Cool and Sleep Well in a Heat Wave

Because of the health risks associated with poor sleep and the fact that we all may be experiencing more hot nights in the future, it's important to have a number of tips at the ready to help cool yourself down when you're trying to sleep during a heat wave.

The first—and likely most obvious—recommendations come with changing the environment you're sleeping in. Research has shown that keeping the room between 20 and 25 degrees Celsius—or 68 and 77 degrees Fahrenheit—are optimal for sleep, so using fans or air conditioning and keeping the room as dark as possible can help you keep your room within that range, the review article said.

The other environmental changes named in the review include:

• Ventilate your space as much as possible when it's cool, and keep windows closed during the hottest times of day
• Limit clothing when you're sleeping, and choose cotton when possible
• Keep your sleep cycle as regular as possible by sleeping only in your bed and staying out of your bed when you're not tired

Other things—including keeping your room quiet and making sure you're sleeping in a comfortable bed—can also keep sleep disruptions to a minimum, Dr. Oyegbile-Chidi added. Though they won't make you cooler, less disruptions can't hurt if the heat is already bothering you.

The review also identified lifestyle changes that can be integrated into daily routines to help lower body temperature:

• Take a short lukewarm shower before going to bed to lower body temperature
• Cool the body with water spray or mist if you wake up in the middle of the night
• Avoid alcohol before bed, as it increases dehydration and night time sweating
• Drink lots of water throughout the day
• Get some physical activity in the morning if it's cool to promote a healthy sleep-wake schedule

Though these tips are fairly simple, they may not work for every person in the same way, the review adds. For kids, hot summer days may lead to later bedtimes and earlier rising times. It's important that parents make sure their kids are still getting enough sleep during these warmer months. A calming activity before bed may also help promote relaxation and the cooling down of kids' internal body temperatures, which will help them sleep better.

For people who are pregnant, the review explained, they may already experience pregnancy-related sleeping issues before and after they give birth. Though all of the above tips still apply to pregnant people, in some situations they may want to avoid the heat by moving to a cooler place for the duration of the heat wave or for the summer, the authors added.

Though these tips are relatively simple, some recommendations presented in the study require that a person have access to power, air conditioning, fans, leisure time, and a stable sleeping environment, which are luxuries that not every person has.

"There [are] certain parts of the nation right now that are dealing with a lot of power outages and such and they may be more common in specific neighborhoods," Dr. Ogeybile-Chidi said. "We really want to make sure that those who are dealing with more outages are able to find a way to still stay cool."

Communities that are less wealthy and have a higher population of people of color tend to be hotter in general, a 2021 study found. Hot days also make it much harder for people who work at night to get restful sleep, Dr. Ogeybile-Chidi added, as they sometimes have to sleep during daytime triple-digit conditions.

More research still needs to be done on which populations are specifically most at risk for poor sleep quality due to heat waves, Baglioni said.

"Regardless of the socio-demographic factors, we want to make sure that we are all prioritizing our sleep and ensuring that we consider this an important factor," Dr. Ogeybile-Chidi said.

No Perfect Solution

Though implementing some— or all—of these recommendations will help with sleep during a heat wave, we can't do much to control the heat. If you're experiencing poor sleep from an extended heatwave and simple environmental or lifestyle changes aren't working, Baglioni and Dr. Ogeybile-Chidi agreed it's best to speak with a doctor to help with your insomnia.

Some changes may work better for some people than others, Dr. Ogeybile-Chidi added, so monitoring your sleep and how you feel will help you determine the best ways to optimize your sleep.

"[Apple Watches or Fitbits] can give you a sense of how well you slept and if you were able to consolidate your sleep and sleep through the night," she said. "You can always make adjustments to your sleep time, like your bedtime routines, the time that you sleep, the time that you wake. Make adjustments to that to ensure that you're having enough time to get good consolidated sleep."

Another reality that makes staying cool so complex is that many cooling tactics such as running air conditioning units and fans—may very well be contributing to climate change, and by extension, heat waves. Air conditioners can increase the outdoor air temperature in some places, and some even emit greenhouse gasses, though they are being phased out.

Despite the issues, though, Dr. Ogeybile-Chidi said, it's never a good idea to sacrifice good sleep and your health to save energy. Cutting down air conditioner use during the day can be a good solution if you're concerned about the environment.

As climate change and heat waves continue to worsen, it's important to have the tools available to keep sleeping comfortably, because your health depends on it. Sleep is just one more aspect of life that is being impacted by climate change, and being aware of it is an important step.

"Good prevention and brief, but straightforward, interventions for sleep behavioral problems may be important," Baglioni said. "Improving sleep health in the general population may contrast and reduce the impact of climate changes on our sleep-wake patterns."