A bath or shower 90 minutes before bed can improve your sleep
If you struggle with falling asleep each night, a warm bath or shower can help you get to sleep sooner and improve the quality of your sleep, according to a new US study.
Researchers at the University of Texas at Austin’s Cockrell School of Engineering reviewed more than 5,300 studies looking at sleep quality and bathing and found that bathing or showering one to two hours before bed can help people fall asleep in less time. On average, they found that bathing hastened sleep onset by 10 minutes.
Researchers say the perfect water temperature is between 40°C and 43°C (104°F to 109°F). If the water is too cold, you won’t sleep as well. So if you like to take cold showers in the summer to cool off, avoid doing so before bed.
Bathing helps you fall asleep by positively affecting your circadian rhythm—your body’s sleep cycle influenced by body temperature, melatonin levels in the brain, and cortisol levels in the blood. (Your body produces cortisol, a stress hormone, when you’re worked up, which why worry can keep you up at night.)
It sounds counterintuitive, but your body actually cools down after a warm bath or shower. That cooling helps you fall asleep sooner. (That’s why it’s important not to keep the heat too high in your room when you’re trying to sleep. Exercising at night also doesn’t help you sleep, since it raises your body temperature.) Researchers found that cooling also improves the quality of sleep, increasing the total time spent asleep and subjects’ perceptions of how well-rested they felt the next day.
The study was published in the journal Sleep Medicine Reviews.