If you have spent months cycling through melatonin, sleep hygiene tweaks and meditation apps without landing on consistent rest, you are in familiar company. Between 10 and 30% of adults deal with insomnia, according to the National Sleep Foundation. That reality has pushed a lot of weary sleepers toward sound as a nightly tool, and the “color” labels you keep seeing on apps and forums are shorthand for how those sounds behave.
Clinical audiologist Amy Sarow, Au.D., told Good Housekeeping, “As sound is not visible, using the color spectrum is a more concrete analogy for these noise colors. White, pink and brown noise contain different amounts of energy across all frequencies [and] function in unique ways to influence our mental states.”
How Noise Color Works
The analogy borrows from light. White light contains every visible wavelength at roughly equal intensity, and white noise does the same with sound by blending every audible frequency. Pink, brown, green, gray, blue and violet are each weighted differently, which is why they sound deeper, softer, hissier or more natural.
Roneil G. Malkani, MD, a neurologist and sleep medicine physician and scientist at Northwestern Medicine, told Northwestern Medicine, “Those who can benefit the most from using noise during sleep are those who are sensitive to noises or who live in places where there is more noise, such as urban areas.”
White Noise and the Research on Sleep
White noise sounds like a steady “shhhh,” a gentle waterfall or the static of an untuned television. Research shows it can meaningfully improve sleep for people in noisy urban neighborhoods by masking sudden sounds.
Several studies also point to a benefit for people with ADHD. One study found white noise enhanced memory performance in children with ADHD symptoms, while the same study found it disrupted children without ADHD symptoms.
Pink Noise for Deeper Sleep
Pink noise sounds softer and more natural than white, closer to rustling leaves, steady rainfall or ocean waves. A 2017 study by the Center for Circadian and Sleep Medicine found pink noise can help people spend more time in deep sleep, which translates to more energy on waking. It is often recommended for light sleepers and anyone who tends to drag in the morning.
Malkani said more research is needed. “There’s much more research to be done to determine the optimal settings and methods of stimulation and determine the viability of the synchronized pink noise as a treatment. However, this is very exciting because this will allow us not only to understand the relationship between sleep and memory but also find new avenues of treatment or optimizing sleep,” he told Northwestern Medicine.
Brown Noise for Racing Thoughts
Brown noise, sometimes called red noise, is deeper still. It sounds like a strong waterfall, heavy rainfall or distant thunder, and insomniacs with a loud mind at lights-out often reach for it first. Malkani told Northwestern Medicine that brown noise sits lower in pitch than pink, which sits lower than white. He added that “when using continuous background noise, it is important to keep the volume just low enough to be audible, but not so high that it would cause arousal from sleep.”
Green, Gray, Blue and Violet noise
Green noise is a variation of white noise built around nature sounds like flowing rivers, rustling leaves and gentle rain. Its lower frequency makes it a popular pick for people kept awake by stress, per Sleepopolis.
Gray noise is calibrated so your ears perceive every frequency at roughly the same volume, per The New York Times. It can sound like wind or steady rainfall and tends to help people who are sensitive to sharp or fluctuating sounds, whether they are trying to focus or trying to drift off.
Blue noise sits at a higher pitch than white, with volume rising as pitch goes up, per Sleepopolis. Violet noise climbs higher still, with volume jumping up exponentially with pitch.
New York-based audiologist Ruth Reisman-Aguilar, Au.D., told Good Housekeeping, “We usually tell patients to test multiple sounds and find which one they prefer and pair that sound with relaxation techniques, breathing exercises, sleeping therapy and mindfulness.”
