Too Hot to Sleep? How Temperature Impacts Sleep

Most of us have experienced the discomfort of waking up in a pool of sweat, especially in Arizona—on an excessively hot or humid night when opening the windows just isn’t an option, and cranking the AC just means paying the consequences (literally) when bill time comes around.

So, if you’re forced to sleep in the heat or just find that you’re not sleeping well in the summer, what’s the solution? Thankfully, there are many different ways to cool down in the evening and maintain a comfortable temperature throughout the night. But for starters, it’s important to understand how temperature affects our sleep in the first place.

Successfully Sleeping in the Heat

According to the National Sleep Foundation, research has shown that there is an ideal temperature for sleep, and when the temperature is very high, it takes longer to fall asleep. Also, once sleep is achieved, if it is broken up or fragmented, the REM cycle is interrupted. 

“As part of a normal sleep cycle, your body temperature will begin to decrease in the early evening. This is tied to circadian rhythm, which regulates your sleep, appetite, mood, and other bodily functions. Circadian rhythm is controlled by a collection of cells in the hypothalamus area of your brain known as the suprachiasmatic nucleus (SCN) or circadian clock.”

During the day, our retinas perceive natural light and send signals to our brain that we should be awake. In turn, this stimulates our bodies’ cortisol production (the alert hormone) and keeps our body temperature at its normal waking level, which is around 98.6 degrees Fahrenheit for most people. 

Once the sun goes down, our eyes begin to perceive darkness and signal our brain accordingly. This triggers the release of melatonin (the tiredness and relaxation hormone) and causes our body temperature to start to dip. By bedtime, our body temperatures continue to decrease during the first two stages of our sleep cycle until it eventually reaches its lowest point, which it maintains for the remainder of the night. 

External temperatures can often interfere with that natural thermoregulation. If your room is too hot to sleep, as it likely is during the summer months, it can cause your body temperature to rise and disturb your sleep. You’re more sensitive to temperatures during the first two non-REM sleep stages and thus more likely to awaken during these stages if you’re feeling hot.

Tips to Help You Sleep in the Heat

1. Prevent excessive heat build-up in the bedroom. If you find it’s too hot to sleep with the windows as-is, use blinds or blackout curtains to keep out sunlight. Keep the windows closed. Use fans for airflow.
2. Choose cotton bed linens. Lightweight and lightly colored bed linens are more breathable than linens made of silk, satin, or polyester and promote ventilation and airflow in the bedroom.
3. Wear lightweight bedclothes—or sleep au naturel. Make sure your bedclothes are lightweight and fit loosely. Cotton is a good fabric choice for these as well as cotton breathes better than other fabrics. Another option would be pajamas made from moisture-wicking materials. Some bed sheets also come in this material which may be a good bedding option as well.
4. Freeze your bedsheets. Place your pillowcases, bedsheets, and blankets in a plastic bag, then put them in the freezer for about 30 minutes before you plan to go to bed. They should stay cool for around 30 to 40 minutes, long enough for you to fall asleep. If this is too chilly for you, maybe just place one or two of the items in the freezer, as opposed to all of them. Avoid getting them wet, however, as wet linens will increase the humidity in the room.
5. Avoid cuddling. Bummer, we know, but those nighttime cuddles increase body heat. If you can’t sleep in the heat, you likely shouldn’t cuddle in the heat either.
6. Take a tepid shower. A tepid shower will cool your body temperature and rinse off sweat so you can lie in bed feeling cool and clean.
7. Keep your feet uncovered. Some people like to sleep in socks, but when it’s too hot to sleep, it is best to avoid them. Feet are sensitive to temperature because they contain several pulse points. If you don’t wish to shower, maybe consider dunking your feet in cold water before hitting the sack to help you cool down.
8. Sleep spread eagle. If you’re not sleeping well in summer, change up positions. Avoid balling up at night to reduce body heat and allow air to flow around the body.
9. Place an ice pack or cool rice sock on your neck or forehead. Slip a cold pack under your neck, or on your forehead to help cool the rest of your body down as well.
10. Encourage airflow with fans. Keep the bedroom door open so as not to trap air in. Position the fan in a corner of your room so that it faces the bed.
11. Keep a spray bottle of water next to the bed. If you wake in the night due to the heat, mist your face and neck to cool down.
12. Avoid exercise before bed. Exercise raises your body temperature and causes you to retain heat. Complete all exercise at least two hours before you plan to hit the hay.
13. Avoid heavy and/or spicy foods. Heavy meals and spicy foods can cause you to feel hotter. Eat a light meal at least two or three hours before you go to bed and avoid anything spicy.
14. Don’t drink ice-cold water. It may sound odd to avoid a cold, refreshing glass of water when you’re not sleeping well in summer, but trust us! Drinking ice-cold water slows digestion and metabolism by constricting blood vessels thus decreasing hydration and your body’s ability to cool off. Drink water that is room temperature instead.
15. Take a hot bath. While soaking in a tub of hot water may not sound ideal when it’s already too hot to sleep at night, this can actually help you cool off before bedtime. But this is most beneficial if done prior to bedtime, not immediately before. Your temperature will decrease as you leave the bath and your body adjusts to the cooler environment. Plus, baths promote feelings of relaxation that can also help you fall asleep faster.

If you find that you regularly struggle to sleep at night and are not feeling rested throughout the day, schedule a consultation with a sleep coach at the Valley Sleep Center. Regardless if it’s too hot to sleep, we can help you determine if your sleep problems are the result of an underlying sleep disorder or medical condition so that you can get the proper treatment and get the quality sleep you need.