The sleep hack trend could be backed by science as it combines a number of techniques
Neil Shaw Network Content Editor
13:03, 13 Feb 2026
People have been showering in the dark
People across the UK have been showering, in the dark before bed in a bid to get to sleep more quickly and more easily – and to stay asleep through the night. The ‘sleep hack’ known as dark showering is now commonly shared on social media as an aid for people who have trouble sleeping.
Anglia Ruskin University lecturer and expert in chronobiology – studying how the body reacts to daily time keeping mechanisms – Timothy Hearn has explained the truth behind the ‘hack’. He said: “There is little research on dark showering as a standalone sleep technique. However, sleep science is clear about two key factors this ritual changes: light and heat. Both can nudge the body toward sleep or keep it alert.”
Timothy added: “Bright light in the evening signals to the brain’s internal body clock that it is still daytime. This delays the release of melatonin, a hormone that helps regulate sleep and is often described as the body’s ‘darkness signal’.”
He said: “Bathrooms are often the brightest rooms in a home. Overhead lighting and illuminated mirrors are designed for precision tasks that are useful in the morning but less helpful late at night. Turning these lights off, or dimming them, removes a strong signal that it is still daytime.”
Multiple studies have shown that exposure to bright or artificial light reduces the sleep hormone melatonin and leads to people feeling ‘alert’. One study showed the reduced ‘sleepiness’ lasted three hours after exposure to bright light.
And it isn’t just room lights, the light from a phone or tablet screen has the same impact.
Timothy said: “If dark showering replaces time spent under bright bathroom lights or scrolling on a phone, it may help simply by reducing evening light exposure. The benefit will be smaller if the shower is followed by time under full lighting to dry hair, choose clothes for the next day and tidy up.”
But he cautioned: “Melatonin does not switch on instantly when the lights go out, and a brief shower will not reset a body clock that has been running late for weeks.”
As well as reduced light, the water itself may help with sleep. Timothy said: “Research on passive body heating, which means warming the body without exercise, has shown that a warm shower or bath taken at the right time can help people fall asleep more quickly.
“A 2019 meta-analysis of 13 trials concluded that about ten minutes in warm water one to two hours before bedtime shortened the time it took to fall asleep by roughly nine minutes and improved sleep efficiency, the proportion of time in bed actually spent asleep. Warm water widens blood vessels in the hands and feet, helping core body temperature drop afterwards, a key signal for drowsiness.”
He added: “Dark showering may also help prepare the nervous system for sleep. Low light reduces the brain’s alerting signals and makes it easier to shift from a state of vigilance, often called the ‘fight or flight’ response, into a calmer ‘rest and digest’ state.”
One study found that just being in body-temperature water slowed the heart rate and put the body into a ‘sleep-ready’ state.
A simpler experiment found a similar effect using only warm foot baths.
Timothy told The Conversation another factor is the sound of running water. He said: “A 2024 analysis found that natural sounds such as rainfall or flowing rivers can lower cortisol, a stress hormone, and stabilise heart rate more effectively than silence. Heat, darkness and soft background noise may therefore combine to signal that it is safe to relax.
“There are important caveats. No large trial has directly compared dark showers with brightly lit showers while measuring objective sleep outcomes, so the idea is based on combining related findings rather than direct evidence.
“People with mobility difficulties may need some light to reduce the risk of slips, and those who experience night-time anxiety may feel uneasy in complete darkness. As with most sleep advice, no single habit is a cure for chronic insomnia. Daytime light exposure, caffeine timing and stress management all play an important role.”
