Penn Study Finds Popular Sleep Noise May Harm Rest

Researchers warn that pink noise machines can reduce REM sleep, especially in children.

Published on Feb. 14, 2026

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A new study from the University of Pennsylvania found that using sound machines or apps that play pink noise can reduce REM sleep, a critical stage linked to emotional regulation, learning, and neurodevelopment. The study suggests these popular sleep aids may have unintended consequences, especially for children who spend more time in REM sleep than adults.

Why it matters

Sound machines and apps that play pink noise are widely used to help people fall asleep or mask environmental disturbances. However, this study indicates these tools may be doing more harm than good by disrupting important stages of sleep, which could have significant implications for health and development, particularly in children.

The details

The study, led by Dr. Mathias Basner of the University of Pennsylvania, examined the sleep patterns of 25 healthy adults in a controlled sleep lab environment. Participants slept under various conditions, including silence, constant pink noise, intermittent environmental noise, and combinations of these. Researchers found that while intermittent environmental noise disrupted deep sleep, pink noise on its own decreased REM sleep. When pink noise and environmental noise were combined, sleep worsened across the board, with participants losing both deep and REM sleep stages.

  • The study was conducted at the University of Pennsylvania in 2026.

The players

Dr. Mathias Basner

A professor of psychiatry at the University of Pennsylvania who led the study examining the effects of pink noise on sleep.

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What they’re saying

“Although the subjects in this study were adults, these findings could be especially pertinent to children. Infants and young children spend far more of their time in REM sleep than adults. Basner worries about the consequences of parents using sound machines as a sleep aid for their kids.”

— Dr. Mathias Basner, Professor of Psychiatry, University of Pennsylvania (whyy.org)

What’s next

Basner says this was only one short-term laboratory study and he wants to take the experiment outside the lab and into real-world environments, especially to those habitual users of sound machines.

The takeaway

This study suggests that while sound machines and apps that play pink noise are widely used to help people sleep, they may actually be disrupting important stages of sleep, particularly REM sleep. This could have significant implications for health and development, especially in children. The findings indicate that earplugs may be a better solution for reducing environmental noise and improving sleep quality.