Science Says Bathing Before Bed Could Be the Key to Great Sleep—As Long as You Time It Right

Maggie Seaver
Taking a warm bath or shower this long before going to bed could help you fall asleep and stay asleep, a new study says. Here’s what you need to know.

Can’t sleep? Science says a well-timed bath or shower could be just what you need for a deep, restful snooze.

It turns out a warm bath or shower isn’t just a cleansing, relaxing bookend to a long day. There’s real science behind the benefits of bathing at night to promote and improve sleep—particularly when it’s timed just right.

You may already know that taking a warm bath or shower (scientifically referred to as water-based passive body heating) before bed can help you fall asleep and stay asleep. A recent sleep study conducted by Shahab Haghayegh, a doctoral researcher in the Department of Biomedical Engineering at the University of Texas, not only verifies that recommendation, but digs into exactly how and when to bathe before hitting the sheets for optimal Z’s.

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Researchers combed through more than 5,000 published studies on the effects of water-based passive body heating on sleep quality, length, efficiency, and onset latency (or, how quickly it takes you to fall asleep)—and found that the ideal pre-snooze bathing routine looks like this:

“[Water-based passive body heating] of 40 to 42.5 degrees Celsius (about 104 to 108.5 degrees Fahrenheit) was associated with both improved self-rated sleep quality and [sleep efficiency], and when scheduled 1 to 2 hours before bedtime, for little as 10 minutes, led to significant shortening of [sleep onset latency].”

Translation: Take a 10- to 15-minute, warm (but not too hot) shower or bath one to two hours before going to bed to help you fall asleep more quickly and stay in a deep, restful sleep through the night. Why? That warm shower will first increase your body temperature, after which your body will experience an even more pronounced decrease in body temperature—that temperature dip is what promotes sleep.

If you’re not sure whether it’s best to shower in the morning or at night, or you’re prone to restless nights and insomnia, you should absolutely give this (free and familiar!) sleep trick a try—in fact, you may already be doing it without realizing.

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