Pink Noise May Disrupt Sleep & Reduce REM, Study Finds

Many people turn to ambient sounds like rainfall or white noise to improve sleep, but emerging research suggests these popular sleep aids may actually be detrimental, particularly to restorative sleep processes. A new study from the University of Pennsylvania Perelman School of Medicine, published February 2, 2026, in the journal Sleep, found that exposure to pink noise—a type of broadband noise often compared to the sound of steady rainfall—reduced the amount of time spent in REM sleep.

The study challenges the widespread use of sound machines and sleep apps marketed as sleep aids, suggesting that these devices may inadvertently interfere with crucial sleep stages. Interestingly, the research also demonstrated that traditional earplugs were significantly more effective at protecting sleep quality when exposed to disruptive noise, such as traffic or aircraft sounds.

The Importance of REM and Deep Sleep

Sleep isn’t a uniform state; it cycles through different stages, including deep sleep and REM (Rapid Eye Movement) sleep. Deep sleep is vital for physical restoration, memory consolidation, and clearing toxins from the brain. REM sleep, often referred to as dream sleep, plays a critical role in emotional regulation, motor skill development, and brain growth. These stages work in concert to ensure individuals wake feeling refreshed and mentally prepared.

“REM sleep is important for memory consolidation, emotional regulation and brain development, so our findings suggest that playing pink noise and other types of broadband noise during sleep could be harmful—especially for children whose brains are still developing and who spend much more time in REM sleep than adults,” explained study lead author Mathias Basner, MD, PhD, professor of Sleep and Chronobiology in Psychiatry at the University of Pennsylvania.

How the Study Was Conducted

Researchers monitored 25 healthy adults, aged 21 to 41, in a sleep laboratory over seven consecutive nights. Participants had eight-hour sleep opportunities each night and reported no pre-existing sleep disorders or regular use of sound to aid sleep. Throughout the study, participants were exposed to various conditions: aircraft noise, pink noise alone, a combination of aircraft noise and pink noise, and aircraft noise while wearing earplugs. Each morning, participants completed tests and questionnaires to assess sleep quality, alertness, and other health effects.

Key Findings: Pink Noise and Sleep Disruption

The study revealed that exposure to aircraft noise alone resulted in an average loss of approximately 23 minutes of N3 sleep—the deepest stage of non-REM sleep—per night. However, wearing earplugs effectively prevented this reduction in deep sleep. More concerningly, exposure to pink noise alone, played at 50 decibels (comparable to moderate rainfall), was linked to a nearly 19-minute reduction in REM sleep.

When pink noise was combined with aircraft noise, the negative effects were amplified. Both deep sleep and REM sleep were significantly shortened, and participants spent an additional 15 minutes awake during the night. This increased wakefulness was not observed when participants were exposed to aircraft noise alone or pink noise alone.

Participants consistently reported that their sleep felt lighter, they experienced more frequent awakenings, and their overall sleep quality declined when exposed to aircraft noise or pink noise. These negative effects were largely mitigated when earplugs were used.

What is Broadband Noise?

Pink noise falls into a category known as broadband noise, which encompasses a continuous stream of sound across a wide range of frequencies. Other types of broadband noise include white noise, brown noise, and blue noise. These noises differ in how they distribute energy across the audible spectrum, influencing their perceived pitch. Many natural sounds, such as rainfall and ocean waves, are examples of broadband noise, as are sounds produced by common household appliances like fans and air conditioners.

Implications for Sleep Health

The researchers emphasize that these findings support the effectiveness of earplugs as a means of protecting sleep from disruptive noise. Up to 16 percent of Americans currently use earplugs to aid sleep. However, the study also underscores the need for further research into the long-term health effects of pink noise and other broadband noise marketed as sleep aids.

The popularity of continuous background noise is substantial. Data indicates that white noise and ambient podcasts account for three million hours of daily listening on Spotify, and the most popular YouTube videos related to “white noise” have collectively garnered over 700 million views. Despite this widespread use, research examining the impact of broadband noise on sleep remains limited and often inconclusive.

Disruptions in REM sleep have been linked to conditions such as depression, anxiety, and Parkinson’s disease. Dr. Basner also highlighted the potential vulnerability of children, who spend a significantly greater proportion of their sleep time in REM sleep compared to adults. This raises concerns about the common practice of placing sound machines near the beds of infants, and toddlers.

“our results caution against the use of broadband noise, especially for newborns and toddlers, and indicate that we need more research in vulnerable populations, on long-term use, on the different colors of broadband noise, and on safe broadband noise levels in relation to sleep,” Dr. Basner concluded.

This study was funded by the U.S. Federal Aviation Administration Office of Environment and Energy through ASCENT, the FAA Center of Excellence for Alternative Jet Fuels and the Environment, project 86 through FAA Award Number 13-C-AJFE-UPENN.