As temperatures continue to hit record highs, you may be tossing and turning more than usual. Some people are more sensitive than others to heat changes, which can disrupt sleep.
Light, stress, and temperature can affect our circadian rhythm, which is our natural body clock that signals when it’s time to rest and wake up. Our core body temperature, which correlates to the body clock, decreases before bed as sleep-promoting melatonin levels rise.
“With the dropping of our core body temperature, our body is really able to go into relaxation,” says Rebecca Robbins, instructor of medicine at Harvard Medical School and scientist at the Brigham and Women’s Hospital. “And true rest gives our organs a break and other vital systems, allowing them to repair.”
A 2019 study shows how the ability to fall asleep, stay asleep, and get enough sleep are all influenced by overall temperature. When the body temperature remains high at night, overall sleep duration is lower, according to the study.
“During certain stages of sleep, our body is not able to regulate temperature, so if we’re exposed to extremes in temperature, we are more likely to wake up,” Robbins says.
Waking up frequently may prevent you from getting into REM and deep sleep cycles and can leave you feeling tired and groggy the next morning, says Dr. Raj Dasgupta, associate professor of clinical medicine at the University of Southern California Keck School of Medicine in Los Angeles. In the summer months, and for those without air conditioning, getting good quality sleep proves challenging, she says.
Experts say the following steps may help you get more sound sleep during a heat wave.
Lower the room temperature
A room temperature between 65 and 68 degrees Fahrenheit is considered the “thermal neutral zone,” in which your body is able to stay asleep and navigate through different sleep stages without disruption.
Keeping a window open at night can also help cool your room and circulate the air. If the air outside is still hotter than inside, consider angling a fan towards the window to help push cool air towards you.
Wear, and sleep in, breathable materials
Your bed linens and pajamas should be made from light, breathable fabrics, like cotton, that don’t retain moisture and promote airflow. Thicker materials, like flannels, will hold heat.
Sleeping naked is also an option, says Robbins.
Drop your body temperature before bed
It seems counterintuitive, but taking a warm bath or shower before bed helps lower your body temperature. However, in hot summer temperatures you may want to try the opposite and see if a cold shower works better.
Experts also say to place an ice pack or cool towel on your neck and wrists before bed, which may help calm your heart rate and get you ready for rest.
Temperature is just one factor that can determine sleep quality. If you have chronic insomnia, talk to your doctor and consider other options like cognitive behavioral therapy (CBT) or medication, says Dasgupta. Overall sleep hygiene—like maintaining a standard sleep and wake-up time, and having a screen-free wind-down routine—is important as well.