If sound only helps you fall asleep, use a timer: once you are asleep, nothing keeps playing. All-night sound is worth considering when something keeps waking you through the night, such as traffic or a partner’s snoring. Either way, keep it quiet. The evidence that continuous noise improves sleep is weak, and a 2026 laboratory study found that pink noise played all night reduced REM sleep.
This guide is about how long to play a sound and how loud. The guide to white, pink and brown noise covers which sound to choose.
What research says about sound that plays all night
Studies of all-night sound are small, use different sounds and levels, and often measure different things. Four of them shape the answer.
| Study | Who and what | What it found |
|---|---|---|
| Riedy et al., 2021, systematic review | 38 studies of continuous white or similar broadband noise during sleep | Results ranged from better sleep to worse. The authors rated the evidence that continuous noise improves sleep as very low quality and noted it may also affect sleep and hearing negatively. |
| Journal of Clinical Sleep Medicine review, 2022 | 34 studies, 1,103 adults: white noise, pink noise and mixed audio | No strong evidence for auditory stimulation. None of the studies reported adverse effects from short-term use. |
| Basner et al., 2026, laboratory study | 25 healthy adults, seven nights each, pink noise at 40 or 50 dBA for the whole night, alone and with recorded traffic-type noise events | Pink noise reduced REM sleep compared with a quiet night. Added to the noise events, it made overall sleep structure worse rather than better. Earplugs prevented most of the effects of the noise events. |
| Stanchina et al., 2005 | Four healthy adults sleeping with recorded intensive-care noise, with and without added white noise | Arousals rose from 13.3 to 48.4 per hour with the recorded noise, and were 15.7 per hour when white noise was added. Arousals depended on how far the sound rose above the background, not on the peak level. |
Put together: steady sound can make sudden sounds less noticeable, which is the case for leaving it on all night. But all-night sound is itself an exposure, it can change sleep structure, and in the 2026 study earplugs did the masking job better. Basner’s team notes that their participants were not used to sleeping with noise and that results from seven nights may not apply to long-term use.
Which to choose
| Your situation | Reasonable choice | Why |
|---|---|---|
| A quiet room, but your mind keeps you awake | A timer slightly longer than you usually take to fall asleep | The sound is only useful until you fall asleep |
| Traffic, neighbours or snoring wake you during the night | All night, at the lowest level that covers the sudden sounds; consider earplugs | Masking works by narrowing the gap between background and peaks |
| You wake at 3 a.m. and want help getting back to sleep | A timer you start again when you wake | Sound plays only during the awake periods |
| A child’s room | Low volume, the speaker well away from the bed; ask your child’s doctor | See the infant sleep machine measurements below |
How loud is too loud overnight
The US National Institute on Deafness and Other Communication Disorders says that sounds at or below 70 dBA are unlikely to cause hearing loss even after long exposure, while long or repeated exposure at or above 85 dBA can. The World Health Organization puts 80 dB for up to 40 hours a week as the safe limit for listening.
Those limits are about protecting hearing. The levels that changed sleep in the 2026 study, 40 and 50 dBA, are far below them. For sleep, the useful rule is to set the sound just loud enough to cover the noise that bothers you, and no louder. A phone’s volume percentage does not tell you the level at your ear, so the WHO suggests checking it with a sound level app.
Earbuds put the sound right at your ear. For personal audio devices, the WHO’s safe listening tips recommend staying below 60% of the maximum volume.
Children need extra care. A 2014 study in Pediatrics measured 14 infant sleep machines at maximum volume: all exceeded 50 dBA at 30 cm, and three exceeded 85 dBA. If you play sound in a child’s room, keep the speaker away from the bed and the volume low, and ask your child’s doctor.
Setting the timer in Relaaax
Relaaax offers 15, 30, 45, 60 or 90 minutes, or No limit. With a timer, the volume fades out over the last five minutes instead of stopping at once. Switching to another track or category does not restart the countdown, so you can change the sound without adding time.
With No limit, the sound plays with the screen locked until you press Stop or your alarm rings. If you set an alarm, the sleep sound plays until it rings and then turns into birdsong or soft bells. The guide to the gentle alarm shows how to set it up.
If you are unsure how long to choose, start with the option just above the time it usually takes you to fall asleep. If you wake when the sound stops, try the next one up.
Test the setup before you rely on it
A sound that stops at 2 a.m. may be the timer doing its job, or the phone stopping the app. Run a short test while you are awake: choose the timer, lock the screen and check what the player shows when you unlock it. The guide to sounds that stop when the screen turns off walks through the checks. If something stopped the sound overnight, Relaaax shows when it happened, and on Android it points to the setting that fixes it.
When sound is not the answer
Sleep sounds do not treat insomnia. The NHS advises seeing a GP about insomnia if changing your sleep habits has not helped, you have had trouble sleeping for months, or it makes daily life hard to cope with. For chronic insomnia, the American Academy of Sleep Medicine strongly recommends cognitive behavioural therapy for insomnia (CBT-I).
If you play sound to cover ringing in your ears, the NHS advises seeing a GP about tinnitus that is regular, getting worse or affecting your sleep, and asking for an urgent appointment if it beats in time with your pulse.
Frequently asked questions
Is it bad to play white noise all night?
How long should a sleep timer be?
How loud should sleep sounds be?
Does Relaaax keep playing with the screen locked?
Pick a timer or No limit, keep the volume low and test the setup with the screen locked before you rely on it.
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