A warm shower before bed has been called an insomnia-breakthrough, that one key habit which can help you sleep the best sleep of your life. But when should you do it? Should you tuck yourself in bed as soon as you get out of the shower? Should you wait a couple of minutes or a couple of hours? And how long should you shower? The answer is conclusive and the explanation is backed by science.
When you take a warm shower before bed, your body’s blood flow increases, especially to your hands and feet. This blood flow leads to a decrease in body temperature. A warm bath simply accelerates this dip in temperature and enhances your natural circadian process.
Why the heat is important is proved by a Swiss study. It found that warm feet and hands led to an early sleep onset. When participants placed a hot water bottle at their feet, it widened the blood vessels on the surface of the skin and increased heat loss—and led to better sleep.
In another study published in collaboration with the UT Health Science Center at Houston and the University of Southern California, the researchers showed that a warm bath or shower significantly improves sleep. But the crucial point here was not that a warm bath helps you sleep better, which is by now a well-known fact, but that the bath must be one to two hours before bed, and preferably 90 minutes before bed. The researchers found that those who took baths were able to fall asleep on average 10 minutes earlier than those who didn’t.
The study’s analysis shows that “water-based passive heating can improve total sleep time, slow wave sleep, subjective sleep quality, sleep efficiency and sleep onset latency, or the amount of time it takes to fall asleep”.
The temperature of our body is not the same throughout the day. It falls, making us sleepy, and rises to wake us up in the morning. This temperature cycle and sleep cycle operates together and is crucial to achieve quick sleep onset and good sleep.
The 90 minutes, the researchers believe, is that perfect time when after a bath, your body temperature cools down to prepare you for sound sleep. And so, scientists say you must allow your body to get ready for sleep after the shower and advise taking a bath an hour or 90 minutes before bed. You also only need to spend five-10 minutes in shower to allow the warm water to heal you.
But here’s a word of caution: The hour and a half leading to bedtime must also be used cautiously. If you allow yourself to drift towards your smartphones, the blue light will interfere with the melatonin production and successfully suppress your body’s natural circadian rhythm—keeping you away from a well-needed shuteye.
Therefore, develop a nightly ritual where before you hit the shower, you escort your smartphone outside the bedroom, and spend the following 90 minutes with family, reading a book or engaging in light, screen-free activity.