Parents everywhere can probably tell you how much they love white noise when it comes to putting their kids to bed, and many adults living in highly populated areas are also big fans. White noise is comprised of a sound that contains equal amounts of all frequencies that humans can hear across the spectrum. Because it covers such a wide range of frequencies, it is also sometimes called broadband noise. But have you ever wondered how it works, and why helps when it comes to falling asleep?
The role of sound in sleep
Sound plays a crucial role in regulating our circadian rhythms. Sudden loud noises can disrupt our sleep, waking us up. On the other hand, continuous, soothing sounds can help us relax and fall asleep faster. This is where white noise comes in.
According to researchers, white noise has been found to soothe infants and reduce crying, improve overall work performance, and even potentially help with symptoms of ADHD.
The colors of noise
Aside from white noise, you might also come across the terms “pink noise” and “brown noise.” All of these sounds span across frequencies, so how do they differ?
Pink noise is lower pitched because its frequencies decrease in power with each higher octave. It has been compared to the sound of a waterfall, with research finding that it helps with cognition and improves sleep in older adults. Other sounds that can be classed as pink noise include light rain, wind, and rivers.
With brown noise (also called red noise), the frequencies decrease twice as much with each octave compared to pink, resulting in an even deeper sound. In trials, it has been compared to heavy rainfall and showers. Thunder is also considered brown noise. There aren’t enough studies on its effect on sleep, though it has been shown to improve cognitive performance as well as relieve symptoms of tinnitus.
How does white noise help you sleep?
Though studies have shown that white noise can help people fall and stay asleep, more research is necessary to understand why. According to Rachel Salas, MD, a sleep expert at Johns Hopkins, “White noise is a steady noise at a steady rate, [blocking] out ambient noise. And you don’t need to spend a lot of money [on it]. There are things that can serve as white noise, like a fan, which does double duty for temperature also.”
One study, however, found that adults listening to white noise fell asleep 38% faster, and another showed it improved sleep quality for critically ill patients. The fact is that despite more studies being needed to understand how white noise improves sleep, be it by possibly synchronizing brainwaves or simply because it helps drown out background noises, there is enough evidence showcasing its efficacy as a sleep aid to be worth a try.
That being said, Dr. Salas notes that white noise machines are considered “sleep luxury items.” If you find that its use is not improving your overall sleep hygiene, it may be time to consult a physician to rule out insomnia or other undiagnosed sleep disorders.