Color us surprised.
Plenty of people use apps and ambient sound machines to reduce clamor and improve their sleep — but not all noise is created equal.
In fact, new research suggests that a particular type could seriously compromise your slumber.
White noise — and all the other color noises, like brown and pink and green — is a steady sound known as broadband noise.
Broadband noise is sound that has a bunch of different frequencies, all playing at once. What sets each of the color noises apart is how much power is given to each frequency.
For example, white noise has the same volume at every pitch. Brown has more heavy volume on low pitches but quieter volume on high pitches.
Pink noise, meanwhile, as volume that steadily increases as the pitch gets higher. It has a lower pitch than white noise, using deeper sounds and lower frequencies to filter out higher sounds and creates a more even, flat sound, think steady rain and wind rustling through trees.
A team from the University of Pennsylvania Perelman School of Medicine collected study participants who had never used noise as a sleep aid before.
They then observed them sleeping with no noise, airplane noise, pink noise, aircraft noise with pink noise, and aircraft noise with earplugs.
Ditch the pink noise
Publishing in the journal Sleep, the team found that listening to pink noise alone led to a nearly 19-minute decrease in REM sleep.
REM sleep is the active, final, dream-filled stage of the sleep cycle and is crucial for mood regulation, memory consolidation, and cognitive function.
“REM sleep is important for memory consolidation, emotional regulation and brain development, 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,” said study lead author Mathias Bassner.
Another warning — especially if you have travel planned
The study also found that exposure to airplane noise was associated with 23 fewer minutes of deep sleep per night. However, earplugs mitigated this loss.
Worse yet, when plane noise and pink noise were combined, both deep sleep and REM sleep were compromised, and participants stayed awake for 15 minutes longer, an effect which was not observed when they were exposed to plane noise or pink noise alone.
On nights when participants were exposed to both pink and plane noise, they reported waking up more frequently and ranked their overall sleep quality as poor.
Based on these findings, Basner and his team suggest not only that earplugs are our best defense against sleep disruption, but also that the use of pink noise and other sonic sleep aids warrants further analysis.
He said that REM sleep disruption is common among patients with depression, anxiety and Parkinson’s disease. Further, he noted that young children spend a significantly longer period in REM sleep, which could amplify the dangers of pink noise.
According to a survey by wellness company Sleep Doctor, 37.2% of parents said their children need some background noise to sleep.
However, previous research has suggested that white noise — and pink and brown noise — may actually harm a child’s language development.
“Overall, our results caution against the use of broadband noise, especially for newborns and toddlers, and indicate that we need more research in vulnerable populations, on long-term use, on the different colors of broadband noise, and on safe broadband noise levels in relation to sleep,” said Bassner.
In lieu of pink noise and in addition to earplugs to aid and abet better rest, experts recommend blackout curtains and an air purifier in the bedroom, screen-time limits, and magnesium glycinate supplementation.
Additional measures for those looking to improve the quantity and quality of their sleep include evening exercise and a diet rich in fruits and veggies.
