The Downside of Pink Noise for Sleep
Many people rely on soft background noise to help them drift off and stay asleep. However, new research suggests that this tactic might not be effective, or could even be harmful.
Researchers at the University of Pennsylvania examined how various sounds, including pink noise, influenced sleep quality. They found that individuals who fell asleep with pink noise actually had significant reductions in their REM sleep compared to those who slept in complete silence. Moreover, pink noise did little to mitigate the disruptive effects of louder noises when compared to earplugs.
In their findings published in the journal Sleep, the researchers emphasized the need for further studies on the long-term effects of broadband noise, particularly for infants and toddlers, as REM sleep is crucial for their brain development.
Understanding Broadband Noise
Pink noise, along with similar varieties like white and brown noise, is categorized as broadband noise. These sounds are constant and encompass a wide array of frequencies but differ in energy distribution. Pink noise tends to resemble soothing sounds like waterfalls or gentle waves.
While many people swear by the health benefits of broadband noise—claiming it masks disruptive sounds and enhances restful sleep—the research is far from conclusive. A review from 2021 conducted by the same team yielded only weak evidence supporting its effectiveness for better sleep, with some studies even suggesting potential drawbacks.
Mathias Basner, the lead author and a professor of sleep and chronobiology at UPenn, expressed his surprise regarding the trend of introducing noise in bedrooms to aid sleep.
The study involved 25 healthy adults aged 21 to 41 in a week-long experiment. Each night, participants tried to sleep under different noise conditions, including only aircraft noise, only pink noise at 50 decibels, combinations of these sounds, and wearing earplugs amidst noise. A control group experienced silence.
As expected, participants struggled with sleep while exposed to aircraft noise, losing about 23 minutes of deep sleep compared to silence. Even pink noise had negative effects, leading to roughly 19 fewer minutes of REM sleep, the stage associated with vivid dreams and memory consolidation.
The worst combination appeared to be aircraft noise paired with pink noise, resulting in not only reduced REM and deep sleep but also approximately 15 minutes of additional wakefulness. Participants reported worse overall sleep quality under this combination. Interestingly, the adverse effects of aircraft noise lessened significantly when earplugs were used.
The Question of Pink Noise
These findings are based on a small sample size, so more extensive research is needed to confirm the effects of pink noise and similar sounds on sleep over time.
Basner did mention that pink noise had some positive effects on deep sleep and minimized disturbances from environmental noise, so it’s not entirely unbeneficial. Nonetheless, determining long-term impacts remains challenging due to the lack of data on prolonged use.
Given its rising popularity—Spotify users reportedly invest millions of hours into white noise listening each day—the researchers contend that such practices may not be fully supported by current evidence. They specifically advise against using these kinds of noises for young children, who spend a significant amount of their sleep in the REM stage.
Looking ahead, Basner and his team plan to investigate various types of broadband sounds and their volumes, aiming to find an optimal mix for improving sleep quality. In the meantime, I hope the next topic for scientific exploration isn’t that comforting glass of warm milk.
