About 30 percent of Americans have trouble sleeping. Shahab Haghayegh, a University of Texas biomedical engineer, was one of them. Sleep eluded him. “I always had a hard time fall[ing] asleep,” he told Discover via email.
Over the counter medications like the hormone melatonin and Unisom, a sedating anti-histamine, can help people get to sleep. But the medicines aren’t long-term solutions for chronic sleep problems. Haghayegh wanted to find a way to get better sleep without relying on medication.
Now, in a new study in the journal Sleep Medicine Reviews, Haghayegh and team say they’ve found a simple solution. Taking a warm bath or shower one to two hours before heading to bed can help people get better rest, faster. But the researchers say timing is key. A rejuvenating dunk too early or too close to bedtime won’t help.
Seizing Slumber
There’s a lot of research suggesting warm baths make drifting off to slumber easier. Many involve surveys and questionnaires from people who have trouble sleeping. But Haghayegh wanted more definitive numbers. He and his team searched through nearly 4,000 publications on the subject to look for hard evidence. They found 17 studies that included the original data and assessed how a warm shower or bath on its own affected a full night’s rest.
After a comprehensive examination of the studies, they concluded that warm baths or showers before bed really do objectively improve sleep. In the studies, people reported having a good night’s sleep after a warm bath. They also fell asleep faster and stayed asleep longer thanks to the sleep aid. But critically, timing was everything.
Cool Off To Nod Off
Our internal clocks spur a drop in body temperature starting about an hour before we typically go to sleep. Temps continue to fall into the night. A warm bath or shower one to two hours before going to bed facilitates the body’s natural flow into sleep by lowering body temperature. Immersing yourself in warm water shunts blood flow to our palms and the soles of our feet and helps heat dissipate from the body.
Taking a warm bath or shower too early before bedtime may make you feel sleepy, but won’t actually help you fall asleep, Haghayegh said. Likewise, a warm bath or shower too close to bedtime may be too late to be effective. It might even interferre with the body’s ability to fall and stay asleep.
For a restful night, the researchers recommend a warm bath or shower – 104 degrees Fahrenheit to 107 degrees F – for as little as 10 minutes, one to two hours before bedtime.
When he can, Haghaeyegh follows his own advice. “It helps,” he said.
