Many people play a soft "shhh" sound called pink noise to help them sleep. In 2026, researchers in the US tested 25 healthy adults in a sleep lab for seven nights.

When pink noise played all night, people had about 19 minutes less REM sleep, the kind of sleep when we often dream. Pink noise also did not protect sleep well from airplane noise. But simple earplugs blocked most of the bad effects.

Pink noise, a soft sound similar to steady rain, is popular as a sleep aid. But is it really good for sleep? Researchers at the University of Pennsylvania studied 25 healthy adults aged 21 to 41, who spent seven nights in a sleep lab. Their brain waves were recorded every night.

On different nights, they slept with environmental noise such as aircraft sounds, pink noise, both, noise with earplugs, or no sound. Compared with quiet nights, pink noise at 50 decibels reduced REM sleep by about 19 minutes. Adding pink noise to the environmental noise made overall sleep structure worse. In contrast, earplugs prevented most of the harmful effects of the noise.

Broadband sounds such as white and pink noise are widely marketed as sleep aids, yet their effects across a whole night have rarely been tested with objective measures. In a study published online in SLEEP in 2026, researchers at the University of Pennsylvania had 25 healthy adults aged 21 to 41 spend seven nights in a sleep laboratory while their sleep was monitored by polysomnography. Conditions included intermittent environmental noise such as aircraft sounds, pink noise at 40 or 50 decibels, combinations of the two, noise with earplugs, and a quiet control night.

Environmental noise reduced deep N3 sleep, while pink noise at 50 decibels reduced REM sleep, which is linked to memory processing and emotional regulation, by about 19 minutes. Combining pink noise with environmental noise slightly reduced brief awakenings but worsened overall sleep structure. Earplugs, by contrast, largely prevented the noise effects, although their benefit began to weaken at 65 decibels. Next-morning cognition, blood pressure, and hearing were unaffected. However, the sample was small, participants did not normally sleep with noise, the study lasted only a week, and concerns about children remain an extrapolation.