You've probably tried it: that gentle whooshing sound playing through your phone at 2 a.m., promising deep, restorative sleep. But new research suggests pink noise might be working against you in ways you can't hear.
A study from the University of Pennsylvania's Perelman School of Medicine tracked 25 healthy adults over seven nights in a sleep lab, exposing them to different noise conditions—aircraft noise alone, pink noise alone, both together, and aircraft noise while wearing earplugs. What emerged was a clear hierarchy of what actually works.
Aircraft noise, unsurprisingly, damaged sleep. It cost participants about 23 minutes of deep sleep (the stage where your brain clears metabolic waste and consolidates memories) each night. Pink noise, on the other hand, seemed like it should help. Instead, it reduced REM sleep—the stage where you process emotions and consolidate motor skills—by roughly 19 minutes. When the two combined, both deep sleep and REM sleep shrank, and people spent an extra 15 minutes lying awake.
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Start Your News DetoxBut here's what worked: earplugs. Simple, cheap earplugs almost entirely prevented the sleep loss that noise caused. Participants who wore them slept through the aircraft noise with minimal disruption to either sleep stage.
The finding matters because REM sleep isn't optional. It's where your brain sorts emotions, builds new neural connections, and consolidates learning. Children spend even more time in REM than adults do. If you're using pink noise as a sleep aid—and millions of people are—you might be trading one problem for another.
The researchers note that broadband noise like pink noise essentially masks sleep's natural architecture rather than protecting it. Earplugs, by contrast, simply block the disruptive sound without introducing a new acoustic environment your brain has to process. About 16% of Americans already use earplugs for sleep, and this research suggests that straightforward approach might deserve more attention than the growing market of sleep sound apps would have you believe.
The team is now investigating the long-term health consequences of regular exposure to these ambient sounds—particularly for children and people with existing sleep disorders. For now, if you're waking up groggy despite hours in bed, it might be worth checking what's actually playing in your ears.
