Sleep aid pink noise may reduce REM sleep, study finds

A University of Pennsylvania study of 25 healthy adults found that pink noise around 50 decibels was linked with about 19 fewer minutes of REM sleep, while earplugs largely prevented deep-sleep loss from aircraft noise.

A University of Pennsylvania team tested how common nighttime sounds affect sleep stages in a controlled lab setting. Researchers observed 25 healthy adults (ages 21–41) across eight-hour nights in a seven-night sleep-lab simulation. Participants experienced aircraft noise, pink noise, aircraft plus pink noise, and aircraft noise with earplugs while researchers measured sleep stages and collected morning surveys. The study examined short-term, nighttime effects rather than long-term use. Key findings: - Pink noise at about 50 decibels was associated with an average decrease of nearly 19 minutes of REM sleep. - Aircraft noise was linked with about 23 fewer minutes of deep sleep compared with no noise. - Combining aircraft and pink noise produced shorter REM and deep sleep and roughly 15 more minutes awake than noise-free nights. - Using earplugs largely prevented the decline in deep sleep seen with aircraft noise. Summary: The study indicates that continuous broadband sounds such as pink noise can alter REM and deep sleep in short-term laboratory conditions. The researchers noted limitations, including a small sample and lack of long-term data, and said more research is needed; undetermined at this time.