If you've ever struggled with sleep problems — and tried every solution Google has to offer — you might be tempted to roll your eyes at the suggestion that taking a bath could improve your sleep. But according to a new study from the University of Texas at Austin, in the U.S., that's very much the case: specially, taking a bath 90 minutes before bed could result in better sleep. Sure, your roommates might skimp on their bathroom-cleaning duties, or have an irritating habit of urgently needing the toilet just when you've settled into the tub. If a meticulously timed bath is the secret to a solid night of sleep? It has to be worth a try.
Researchers from UT's Department of Biomedical Engineering assessed 5,322 existing studies associating warm baths and showers with better sleep, publishing their findings in the journal Sleep Medicine Reviews. Shahab Haghayegh, the study's lead author, said in a press release, "When we looked through all known studies, we noticed significant disparities in terms of the approaches and findings," adding, "The only way to make an accurate determination of whether sleep can in fact be improved was to combine all the past data and look at it through a new lens."
From the existing studies, the researchers isolated data on the impact of "water-based passive body heating" — basically, a warm bath — on sleep quality. Specifically, they targeted four aspects of sleep: total sleep time, subjective sleep quality, sleep onset latency — how long it takes to progress from being awake to being completely asleep — and sleep efficiency, or the amount of time actually spent asleep in relation to "the total amount of time spent in bed intended for sleep."
Their findings? A bath taken one to two hours before bed — ideally, 90 minutes — improved sleep quality. What's more, it sped up falling asleep by 10 minutes on average (and 10 minutes, when you're trying to fall asleep, feels like 10 lifetimes). The perfect bath temperature, meanwhile, was between 104 and 109 degrees Fahrenheit, or 40 to 43 degrees Celsius.
The sleep-boosting impact of a warm bath is all down to the circadian rhythm, or the sleep/wake cycle. Body temperature, the researchers explained, typically drops about an hour before you fall asleep, dropping further as you sleep before beginning to rise — "acting as a kind of a biological alarm clock wake-up signal," as the UT press release puts it.
Taking a warm bath increases your blood circulation, allowing heat to move away from your core and thus your body temperature to decline. Timing a bath before bed correlates with the natural drop in body temperature occurring at the same time, supporting your sleep/wake cycle and improving your sleep. Simple!
If you still can't be tempted by a soak, consider these other health benefits: baths can ease skin conditions like eczema, alleviate muscle, arthritic, and other chronic pain, boost your mood, and relieve cold symptoms (I promise I am not sponsored by Lush.) Get those taps running, friends! The tub is calling.