Pink noise is a type of sound that contains a random assortment of all the audible frequencies, with more power in the lower frequencies. Specifically, pink noise contains the same overall intensity in each octave, but the volume of individual pitches decreases by 3 decibels with each higher octave. Pink noise is often compared to water and nature sounds, such as rustling leaves, steady rain, ocean waves, and heartbeats. Pink noise has a kind of natural ebb and flow, and its intensity decreases as frequency increases, making it more pleasing to the human ear than white noise. Pink noise is often considered more relaxing than white noise, since it does not sound as high-pitched.

Pink noise is often used as a background or control noise because research has found that it is less distracting than other types of noise. For example, one study found that participants became less stressed after listening to pink noise, compared with the typical sounds of an intensive care unit. Emerging research indicates that pink noise may also have benefits for sleep. In a study, a link was found between pink noise and deep sleep. This may be because pink noise is especially relaxing when used to drown out unwanted sounds and outside noises that could interfere with a person’s sleep.

Examples of pink noise include rustling leaves, steady rain, ocean waves, and heartbeats. Pink noise is often used as a sleep aid, and there are many options for adding it to your sleep routine, such as getting a noise app from your smartphones app store or using comfortable headphones for falling asleep to pink noise.