Many people rely on ambient sounds like rain, static or other constant noises to help them fall asleep. These sounds are very popular across many platforms, like sound machines and apps. Many people are often recommending these as a sleep aid when they have trouble sleeping, but recent research has found that one, pink noises, might not be as beneficial as people had thought.
Pink noise is very similar to white noise in the sense that they both play frequencies that humans can hear. White noise plays all frequencies, 20Hz to 20,000 Hz, at the same intensity, or strength, whereas pink noise plays more of the lower frequencies, and has often been compared to ocean or rain sounds. The question might come up; why are these noises named after colors? Well that is because their color is matched up with how their noise spectrum matches with a colored light spectrum.
A new study by the University of Pennsylvania did a study to see how pink noise, environmental sounds and ear plugs affected sleep quality. The participants were 25 healthy adults, who were placed in a lab for 7 days and had their sleep recorded. None of the people had sleep disorders or normally slept with sound machines before the experiment.
A very surprising result of the experiment was the REM sleep was significantly reduced, by about 19 minutes a night, with the addition of pink noise. REM, rapid eye movement, is the most important part of a human’s sleep cycle. It is when memories get sorted and the brain develops. This is the deepest part of the sleep cycle; lots of dreams happen during this. Losing time in this stage could mean waking up less refreshed and the brain could have a problem processing some information.
This doesn’t mean all sound machines are horrible and have the same effects for everyone. This study was done on a very small group of people and the researchers changed what noises the participants were listening to every night. Scientists say that more research needs to be done on how these sounds affect the brain, especially in children.
