Noise can destroy our slumber. That barking dog next door makes it feel impossible to get to sleep. Once you’re finally snoozing, an ambulance driving by can jolt you back awake.
Not all noise is bad for our sleep, though. Certain ambient noises, known as color noises, are thought to be sleep aids. Beloved by parents of young children and by adults themselves, color noises, including white noise machines, have become a go-to solution for falling asleep faster and staying asleep due to their ability to block sleep-disrupting noises. Fans liken the sounds to natural sounds, such as rushing water or wind, which can be calming. Some people say they’ve also found other benefits, such as relief from anxiety, racing thoughts, and ADHD from white noise, pink noise, brown noise, and other broadband sounds.
The origin of color noise
People have explored the connection between color noises and better health for centuries. Italian sculptor Gian Lorenzo Bernini invented the first machine using white noise principles to treat insomnia in the 17th century, even though “white noise” wasn’t identified as a concept until the 1920s when engineers began using it as a test signal. Some 40 years after that, the first at-home white noise machines for sleep became available for purchase.
What does science say about color noise?
Given its long history, you’d think scientists would have a clearer understanding of what white noise does to our sleep, brains, and health. But so far, the studies on color noises have been extremely limited, making it difficult to scientifically prove all anecdotal health benefits people claim they provide, including their purported ability to improve sleep.
Anecdotal reports aside, scientists are still investigating color noises and their potential to provide better sleep and relaxation. In a 10-person study of adults in New York City, white noise was found to improve wake-after-sleep onset and sleep latency for those who complained of environmental noise disruptions. A 40-person study found that pink noise induced more stable sleep.
“There’s not enough good science out there to make that conclusion,” said Dr. Mathias Basner, professor of psychiatry at the University of Pennsylvania Perelman School of Medicine, who has co-authored a systematic review of broadband noise as a sleep aid. “A lot of the studies on color noises don’t even properly describe what kind of broadband noise they use. A lot of them are based on self-reported data, not objectively measured sleep.”
He added that all of the studies he looked at were conducted over a very short term, making it impossible to find answers about how color noises may affect us in the long run. So, it’s important to take many of the claims about the benefits of noise colors with a grain of salt.
What exactly are color noises?
To understand how color noises might affect us, it helps to know what they are. Color noises, at least the most popular ones like pink, white, and brown, are broadband sounds that include all the frequencies a human ear can hear.
Each color noise differs in the parts of the audible frequency spectrum which they emphasize. White noise, for example, emits all the frequencies with the same intensity. Since high-frequency sounds tend to be perceived as louder than low-frequency sounds of the same volume, that can make white noise sound high-pitched and somewhat unpleasant to many. Pink noise lowers the strength of higher frequencies. That can make it sound more pleasant and soothing.
Overall, they all tend to have a static-like sound that blocks out other noises. This phenomenon is called “auditory masking,” which may provide insight into some potential health benefits of color noises.
“If you live in a house near an ambulance or with squeaky pipes, those changes in sound can wake you up. A full-frequency or broadband sound, like white, pink, or brown noise, helps you stay asleep because it masks those changes in sound,” explained Dan Berlau, Ph.D., professor of pharmaceutical sciences at Regis University, who has researched the effect of white noise on children with ADHD.
That masking effect may do more than just help us stay asleep. Color noises could also drown out things that distract us when we’re studying or working or sounds that trigger our anxiety, potentially helping our concentration and keeping us calm. Some also find the color noises to be super soothing, making it easier to relax.
Science has yet to find conclusive evidence for most health claims people say color noises offer, but many individuals say specific sounds have offset their specific troubles. For example, they might use white noise for focus, green noise for studying, pink noise to drift off to sleep, and brown noise to curb overthinking. But don’t think of these anecdotes as a prescription for noise therapy, experts warn.
“There’s no scientific evidence that any of these color noises work differently or do anything different from one another,” said Berlau.
But that’s no reason to shy away from using it if it’s helpful to get you to drift off. “If listening to brown noise causes you to relax, which causes a reduction in cortisol, then that’s working scientifically as far as I’m concerned. Reducing the level of cortisol will have a physiological effect on your body and brain,” Berlau added.
The same is true for pink noise, white noise, and any other noise color you decide to listen to.
Popular color noises
Each color noise is unique in its sound and frequencies. Here’s a guide to the most popular color noises and what they sound like to help you find the one you may like best.
White noise plays all the frequencies of sound the human ear can hear at about the same intensity. It sounds like a continuous hiss, like static on a TV. It’s often used to block distracting sounds in noisy environments and enhance privacy in sensitive places, like a therapist’s office.
Like white noise, pink noise contains all the sound frequencies you can hear, but it lowers the intensity of higher frequencies. That makes for a gentler sound that reminds some people of waves on the seashore, leaves rustling in the wind, or steady rain.
Also known as red noise, brown noise sounds deeper than pink and white noise. It increases the strength of lower frequencies on the noise spectrum, making it sound even deeper than pink noise. Some describe the sound of brown noise as similar to a rushing waterfall or thunder.
Blue noise (along with its close sibling, violet noise) is sometimes considered the opposite of brown noise because it intensifies the frequencies at the high end of the spectrum. It can sound like water coming out of a faucet or sprinkler.
Gray noise adjusts the intensity at both the high and low ends of frequency of the audio spectrum. It’s designed so that each frequency sounds equally loud to the average human ear. Gray noise sounds similar to white noise but a little less hissy.
Other color noises
As you search for color noise tracks, you may encounter other hues, like green noise. These aren’t defined as clearly as some color noises, but they may be useful tools to help you concentrate, relax, or tune out distractions.
Tips for Using Noise Colors
While scientists and researchers are still looking into the full scope of color noise and its impact on sleep, it can certainly provide consistency in your sleep environment by masking other sounds. Basner’s 2020 systematic review found very low-quality evidence that white noise can improve sleep, along with some evidence that playing continuous noise in the bedroom may even disrupt sleep or cause hearing loss.
“[Using color noise for sleep] may be detrimental in some people and may work in some people. The information is really incomplete,” he said.
Still, he doesn’t discourage people from experimenting with color noises for sleep as long as they follow a few safety guidelines. Here are some tips on maximizing the sleep benefits of color noises (and reducing the risk of harm).
- Keep the volume low: The CDC warns that hearing noises above 75 decibels over eight hours can increase your risk of noise-induced hearing loss. That’s about the volume level of a dishwasher or washing machine. If you need to shout to be heard by someone near you while playing a colored noise, the volume is probably a little too loud.
- Test different noise colors: When two people listen to the same color noise, they may experience it in very different ways. White noise, for example, may be overstimulating for one person, while it’s the perfect sound to tune out distractions for someone else. Experiment with different noise colors to see which works best for you.
- Find accurate noise color tracks. Many color noise tracks you find online are mislabeled, warned Berlau. Finding ones that are accurate can help you know which color noises are your cup of tea.
- Use noise colors consistently. Research shows that consistent bedtime patterns can benefit your sleep and overall health. If you’d like to incorporate a noise color into your sleep routine, try to play the same sound at the same volume and time every night. That can help teach your brain to get ready for slumber anytime you hear that sound.
- Don’t listen to color noises when driving. Tempting as it may be to stream color noises when you’re trying to stay calm in traffic, it’s not safe to play them when driving, Berlau advised. Color noises could mask exterior sounds (like a car horn), putting you at risk of a crash. Same goes for biking too.
- Play it at the lowest volume possible. Loud sounds can damage your hearing. And, not to mention, it probably won’t help you drift off.
- Put your noise machine on a sleep timer. Basner warns that continuous noise overnight could make it difficult for your auditory system to recuperate. More research is needed, but it may be safer to rely on color noise to lull you to sleep rather than stay asleep all night, so set a timer to switch off your noise machine 30 to 60 minutes after bedtime.
- Be mindful of sleep disturbances. Color noises may cause sleep disturbances in some people. Use a sleep-tracking device or a journal to keep track of any sleep troubles you experience when experimenting with color noises. If a noise seems more disruptive than helpful, it might not be right for you.
- Avoid long-term use. Scientists have yet to study whether long-term use of white noise or any other noise color could cause harm. So, while it may be good at a noisy hotel or for a night when a loud party is going on next door and you’re experiencing ongoing sleep problems, talk to a medical professional to get to the root of the issue and find a safe, effective treatment, rather than relying on color noise to solve the problem.
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