Pink Noise & Sleep: Does It Disrupt REM?

Pink noise, often touted as a soothing sound to aid sleep – reminiscent of rainfall or a gentle waterfall – may not be the sleep solution it’s often made out to be. A new study suggests this popular ambient sound could, in some individuals, disrupt the restorative processes that occur during sleep, specifically impacting REM sleep.

Researchers at the University of Pennsylvania conducted a study examining the effects of pink noise on sleep quality. Their findings, February 2, 2026, revealed that pink noise can shorten REM sleep in certain individuals.

What is REM Sleep and Why Does it Matter?

Sleep isn’t a uniform state. it cycles through different stages, including light sleep, deep sleep, and rapid eye movement (REM) sleep. REM sleep is a particularly active phase of sleep characterized by vivid dreaming, increased brain activity, a faster heart rate, and temporary muscle paralysis. It’s a crucial period for several cognitive functions.

“REM sleep is important for memory consolidation, emotional regulation and brain development,” explains Dr. Mathias Basner, MD, PhD, professor of Sleep and Chronobiology in Psychiatry at the University of Pennsylvania Perelman School of Medicine. “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.”

The Study Design

The study involved 25 healthy adults, aged 21 to 41, who were monitored in a sleep laboratory over seven consecutive nights, with each night providing an eight-hour sleep opportunity. Participants reported no prior use of noise to aid sleep and had no existing sleep disorders. Throughout the study, participants were exposed to various conditions, including aircraft noise, pink noise, a combination of aircraft noise and pink noise, and aircraft noise paired with earplugs. Each morning, participants completed tests and surveys to assess sleep quality, alertness, and overall health effects.

Key Findings: Pink Noise vs. Earplugs

The research demonstrated that pink noise reduced REM sleep. Specifically, the study found that pink noise cut REM sleep by approximately 19 minutes. In contrast, earplugs proved significantly more effective in protecting sleep against disruptive noises like traffic and aircraft sounds.

The study challenges the widespread marketing of ambient sound machines and apps as sleep aids. While these devices are often promoted for their calming effects, the research suggests they may inadvertently interfere with the restorative benefits of sleep.

Why Might Pink Noise Disrupt Sleep?

The exact mechanism by which pink noise disrupts REM sleep remains unclear. However, researchers speculate that the “constant auditory input” may inhibit the brain processes responsible for entering and maintaining REM sleep. The brain cycles through periods of deep sleep and REM sleep, and constant stimulation may interfere with this natural progression.

What Does This Mean for Sound Machine Users?

The findings raise questions about the long-term effects of regular pink noise exposure during sleep. While occasional use may not be detrimental, consistent reliance on pink noise could potentially compromise sleep quality and hinder the cognitive benefits associated with adequate REM sleep. Here’s particularly relevant for children, whose developing brains require sufficient REM sleep for optimal growth and development.

The study suggests that individuals seeking to block out disruptive noises may be better served by using earplugs, which demonstrated a more protective effect on sleep quality without interfering with REM sleep.

Beyond Pink Noise: Considerations for Sleep Hygiene

This research underscores the importance of prioritizing good sleep hygiene. Beyond addressing external noise, factors such as maintaining a regular sleep schedule, creating a relaxing bedtime routine, and optimizing the sleep environment (temperature, darkness, and comfort) are crucial for promoting restful sleep. If you are consistently struggling with sleep, it’s important to consult with a healthcare professional to rule out any underlying sleep disorders.

While pink noise may offer a temporary sense of calm, this study provides compelling evidence that it may come at the cost of restorative sleep. For those seeking a peaceful night’s rest, earplugs may offer a more reliable and beneficial solution.