People use various types of noise to help them sleep. But what noise can best induce sleep? In the following article, we’ll examine sleep research that concerns white noise and pink noise.
What is white noise?
White noise—volume that remains constant regardless of frequency, such as high-pitched static—is random patterns of sound that reside in a certain frequency range. It’s essentially a combination of all the sound frequencies that a human ear can hear. When a person hears this combination, it typically sounds similar to a waterfall.
Why people use white noise
White noise has the ability to “drown out” louder noises. These other noises—traffic, a neighbor’s television, etc.—can cause nighttime arousal. When white noise is playing in a person’s bedroom, it can help muffle outside sounds and unusual noises, and induce sleep.
A study from 1990 in the journal Archives of Disease in Childhood found that white noise helped neonates fall asleep. Another study from 2016 in the Journal of Caring Science discovered that white noise helped mask environmental noises in a coronary care unit, a very busy unit in hospitals. This “noise masking” helped improve the sleep of patients in the unit. And another 2004 study in the journal Sleep Medicine also discovered that patients exposed to white noise slept better because white noise effectively hides “background noise” and other “peak noises”.
What is pink noise?
Pink noise—classified as noise that’s volume decreases by 3 db per octave, such as thunder—is similar to white noise in that it’s random noise. However, with pink noise, higher frequencies have less spectral power than lower frequencies.
Why people use pink noise
People may use pink noise because it is said to better induce sleep. However, research that supports this claim is more limited than white noise sleep research.
For example, a 1991 study in the the Journal of Sound and Vibration posits that sleep under a steady noise is deeper because of an inhibition pulse from the brain’s cortex that may suppress the activation of reticular formation. However, the meaning of this “depressed proportion of REM under steady pink noise” wasn’t apparent in the study.
But another study that was published in 2012 in the Journal of Theoretical Biology discovered that steady pink noise could help reduce brain wave complexity. It also found that pink noise could induce more stable sleep, and improve sleep quality. And a 2013 study in Neuron found that research subjects who were exposed to pink noise when they were in deep sleep stayed in “deep sleep” longer than subjects exposed to no noise.
Is pink noise or white noise better for sleep?
Although it’s said that pink noise may better induce sleep, the research supporting this assumption is minimal compared to white noise research. So, it may be best to use white noise to induce sleep, as there is more research to back up its effects.
However, remember that everyone responds to “noises” differently. What works for one person may not work for you. So, be open to noise experimentation.
If you’re interested in purchasing a white noise machine, consider consulting our comprehensive white noise machine review guide.