During the summer months, many of us find ourselves tossing and turning for hours trying to get to sleep.
If you've ever wondered why this is, it's all to do with our circadian rhythm.
Why Can't I Sleep in the Heat?
"During the normal human circadian rhythm, sleep occurs when the core temperature is dropping," Katherine Hall, a sleep psychologist at Somnus Therapy, tells Newsweek.
"This drop in temperature starts about two hours before you go to sleep, coinciding with the release of the sleep hormone melatonin.
"Unfortunately, hot weather can make it a lot harder to cool down."
Temperatures higher than 72.5 F can cause restlessness when you try to sleep, she explains.
"You may feel sweaty and experience hot flushes throughout the night causing you to constantly toss and turn."
The heat also slows important physiological processes like your heart rate and breathing, Robert Pagano, co-founder of Sleepline, adds.
"Slower body processes mean that it takes longer for muscles to become relaxed, leading to a heightened sense of tension before bed and increased sleep-related anxiety."
Should I Sleep With a Fan On?
Cooling down your bedroom is a smart idea, and one easy way to do that is with a fan.
"The National Institutes for Health advises keeping the temperature in your home at or below 80 F, so a fan can often be a lifesaver to maintain comfort during hot weather," Pagano explains.
"Cooling down the house doesn't just happen naturally when you throw open windows; cooling depends on air circulation. A good way to create this is by blowing air with electric fans."
Additionally, the hum of a fan may act like white noise, making it easier to fall asleep.
If you are choosing a fan for your bedroom, Hall offers this advice: "Ideally, you should choose an oscillating fan that is kept around 3 feet away from your bed."
There are drawbacks to sleeping with a fan on though, as they can often make the air dryer.
"This can lead to dry mouth, nasal passages, and throat. The body's response to that is often an overproduction of mucus, which could mean waking up with congestion," says Alex Savy, sleep science coach and Founder of SleepingOcean.
If it's pointed to your face, it can also dry your skin out and trigger allergies, as Hall adds: "Fans can also trigger allergies for some people as fans can circulate dust and pollen throughout the room. If inhaled, you could experience a runny nose, sneezing or a scratchy throat."
To avoid this, it's important to keep your fan clean.
How Can I Stay Cool When Trying to Get to Sleep?
In line with our circadian rhythm, you should start trying to cool yourself down two to three hours before going to bed, says Bruce Forman, a psychologist who specializes in treating insomnia.
He recommends "setting the air conditioning a couple of degrees cooler, using fans, and wearing less clothing.
"Physical exercise should be avoided within three hours of bedtime because it raises body temperature."
Counterintuitively, taking a warm bath or shower can aid the cooling process, as Hall explained: "The hot water brings the circulating blood to the surface of the body, which is one of the quickest ways to drop core body temperature. So as our bodies cool down from a warm bath or shower, our circadian rhythm is signaled to begin making us sleepier.
"The drop in body temperature causes our body to slow down our heart rate, breathing rate, and digestion—getting our bodies into the perfect rhythm for optimal sleep."
Another low-cost method to cool down is using ice packs.
"Placing ice packs on pulse points before sleep can help users cool down just enough to fall asleep fast," Savy says.
"The pulse points include wrists, ankles, back of the knees, and crooks of the elbows."
Hall adds that choosing pajamas made of soft fabrics like silk or linen can help keep you cool, too.
