As summer temperatures rise, so do the challenges of getting a good night’s sleep. Tossing and turning in the humidity, sweat, sticky sheets, and the struggle to fall and then to stay asleep—the nightmare is real. Add to that the tendency to sleep less overall during the summer increases our risk of sleep debt. 

Longer days mean that we go to bed later. Some of us might push our wake time, but most of us can’t. Just 15 minutes of lost sleep adds up to an entire night’s sleep over a month. It seems like a small thing, but it can greatly impact how we feel.

Finding ways to sleep in the heat and maintaining good sleep hygiene is essential to having the energy to enjoy everything the summer has to offer. Let’s look at the connection between temperature and sleep and some tips for cooling down.

Body Temperature and Sleep

Our bodies have an internal clock known as the circadian rhythm, a roughly 24-hour cycle that influences various physiological processes, including sleep. Not to get too technical, but this rhythm is regulated by the brain’s suprachiasmatic nucleus (SCN), located in the hypothalamus, which responds to light cues from the environment to help determine when we feel awake and when we feel sleepy.

Thermoregulation is the process by which our body maintains its core internal temperature within an optimal range, despite external temperature changes. This process involves reactions such as sweating to cool down or shivering to generate heat. It’s the reason we don’t melt when we walk out of an air-conditioned building onto a sweltering sidewalk.

The circadian rhythm and thermoregulation work together to regulate sleep. As part of the circadian rhythm, our body temperature naturally fluctuates throughout the day. It typically peaks in the late afternoon and then begins to drop in the evening, reaching its lowest point in the early morning hours. This drop in body temperature signals the body that it’s time to sleep, promoting drowsiness and making it easier to fall and stay asleep.

However, when the temperature is too high, it can interfere with this natural cooling process. This is why sleeping in a cool environment is best for optimal sleep.

The Ideal Sleeping Temperature

Research suggests that the optimal bedroom temperature for sleep is between 15-19 degrees Celsius (60-67 degrees Fahrenheit). This range supports the body’s natural cooling process and promotes better sleep. However, keeping your bedroom cool during a heat wave is no joke, especially without air conditioning. We have some tips coming up later in this article to help.

Why Heat Affects Our Sleep

When it’s too hot, your body has to work harder to maintain its core temperature.

If your core temperature cannot drop 2-3 degrees before sleep, your brain doesn’t get the signal that it’s time to sleep. Hence, the tossing and turning you experience trying to sleep in a hot, humid bedroom.

Even if you do eventually fall asleep, the heat will affect the quality of your sleep. The drop in body temperature not only helps us fall asleep but, once there, helps us reach slow-wave sleep. During this stage, our bodies repair and grow tissue, muscle, and bone. When we are too hot, it is more likely that we will stay in the lighter stages of sleep. During light sleep, we are more likely to awaken and toss and turn—we just aren’t getting the quality sleep we need to feel energized and alert.

Heat also affects REM sleep. Usually, you will experience most of your REM sleep at the end of the night. This stage of sleep is particularly sensitive to temperature. While in REM, your brain is very active and we do most of our deep dreaming, while our bodies go into sleep paralysis to prevent us from acting out those dreams.

During sleep paralysis, most of the regulation behaviors like sweating or shivering stop. A warm room leads to less REM because the body needs to focus on temperature regulation instead.

Like slow-wave sleep, REM sleep is pretty essential. During this stage, we process our emotions, memories, and learnings from the day. After a night spent mostly in light sleep, we wake up groggy and tired. We are more prone to be irritable and unable to concentrate. A bad mood can ruin a great day. That’s why preparing to sleep in warmer weather is vital to our summer sleep routine.

Sleeping in the Heat

Blasting the air conditioning, if you’re lucky enough to have it, seems like a quick fix, but it’s not ideal for the bank account or the environment.   There are some techniques for all us to help keep from overheating:

Use Breathable Bedding: Choose lightweight, breathable sheets and blankets made from natural fibers like cotton or linen. These materials help wick away moisture and keep you cool throughout the night.

Cool Down Your Room: If you don’t have air conditioning, use fans to circulate air and create a cooling effect. You can also try placing a bowl of ice in front of the fan for an extra cooling boost. Use blackout curtains to block out sunlight and keep your bedroom cool during the day. Open a window after the outdoor temperature drops; letting in some cooler air will make your room less stuffy. If possible, sleep on the lowest level of your home, as heat rises.

Keep Yourself Cool: Use a damp washcloth or ice pack on pulse points, such as wrists, neck, and temples, to cool down quickly. This might sound crazy, but putting your sheets into a plastic bag in the freezer before bed will make them icy cool and instantly refresh you when you slide into bed. Hot water bottles aren’t just for tummy aches—try freezing one to help cool down your body temperature, but place it next to you in the bed, not directly on your skin.

Hydrate Wisely: Stay hydrated throughout the day, but avoid drinking large amounts of water right before bed to prevent nighttime awakenings.

Take a Shower: Depending on who you ask, you will get different advice on this one. A warm (not hot) shower will initially raise your body temperature but may help you cool down before sleep. A cool (not cold) shower can make you feel immediately more comfortable by removing any stickiness or sweat, helping you relax before sleep. Do what works for you! But avoid too hot or too cold showers. Too hot, and you will raise your core temperature so high that it will be harder to cool down; too cold, and the shower can have a stimulating effect, making it harder to fall asleep.

Pajamas or Au Naturel: Wear lightweight, loose-fitting pajamas made from breathable fabrics. This can help your body cool down and reduce night sweats. Sleeping naked also helps with temperature control, and you won’t have to worry about waking up in sweat-soaked pajamas.

Ready to Conquer the Heat?

If there’s one thing to keep in mind for sleeping well during the summer, it’s that staying proactive is key. By understanding how high temperatures can affect your sleep quality and duration, you can better prepare for the next heat wave.

The great news is that many of the strategies for staying cool are easy and inexpensive. Simple adjustments like an evening shower or sleeping with a frozen water bottle can help you manage the heat and improve your chances of getting a good night’s sleep.

When all else fails on those sweltering summer nights and you wake up feeling sticky, a cold shower is a great way to start your morning. Not only will it cool you down, but it will also help you feel more awake and alert to tackle your day.

At Sleep Therapeutics, we’re dedicated to helping you achieve your best sleep. If you’re facing challenges with your sleep, contact us today.