White, pink and brown noise for sleep: What's the difference?

Struggling to fall or stay asleep? You're not alone. According to the Centers for Disease Control and Prevention, nearly 15 percent of U.S. adults have a hard time falling asleep and even more find it difficult to stay asleep, especially those who are over 45 years old.

You may think you've tried everything to improve your sleep quality — a dark, cool room , no eating or screen time before bed and limiting caffeine — to no avail, but have you stepped into the world of colored noise for a better night's sleep?

You may have heard of using white noise to help mask sounds that could interrupt your shut-eye, but white noise isn't the only option. There are several different colors of noise that the human ear can register at varying frequencies, some reported to produce different effects, particularly when it comes to sleep. The most commonly referenced colors of noise are white, pink and brown, with blue, green, gray and black noise being less well known. 

What makes these noises special is that they remain on the same level and frequency while you listen — they don't change frequencies like, say, a truck driving by your bedroom at night or a baby crying in another room. "The good thing about these noises is they stay the same when you turn them on," says Dr. Anupamjeet Sekhon , a sleep and family medicine physician at Kaiser Permanente in Southern California. This enables them to help support sleep by masking other ambient noises, preventing them from cutting through your slumber, says Sekhon.

Ready to dive into the spectrum of colored noise? Read on before you invest in a fancy sound machine.

What is white noise?

"White noise is steady static background noise," says Sekhon. "If you put your radio to a dead channel and you hear that static, that's white noise." White noise contains a mixture of low and high frequencies the ear can hear , all played at equal power, creating that static or "sh" sound you recognize. White noise machines mimic that sound, which may calm the listener.

White noise for sleep

While the studies are limited suggesting white noise actually induces deep sleep, white noise has risen in popularity as an anecdotal sleep aid, as well as a possible treatment for tinnitus , according to Harvard Health Publishing.

However, volume matters. If the decibel level of your white noise is higher than 70 dB, it may actually be detrimental to sleep and hearing . Just keep in mind that anything over 70 dB is fairly loud — 75 dB may sound like a vacuum cleaner running . If your sound machine is set to a volume lower than, say, a typical conversation, you're probably in the clear. 

What is pink noise?

So, how does pink noise differ from white noise? "Pink noise is a lower frequency. The lower pitches are louder in pink noise — like rustling of leaves, steady rain or ocean waves," says Sekhon. Where white noise can be an almost harsh static, pink noise is more of a quiet roar.

Pink noise for sleep

While used less commonly for sleep, pink noise has been recommended as a learning aid, particularly for older adults and those with ADHD. One study published by the Institute of Electrical and Electronics Engineers suggests that pink noise increases memory recall in older adults by enhancing beta and gamma brain waves. Pink noise is believed to induce deeper sleep by mimicking the same brain waves you experience during restorative sleep; however, the actual research is limited.

What is brown noise?

"Brown noise is a lower, deeper, more basslike heavy frequency — rumbling and roaring like a strong waterfall or like a heavy rainfall," says Sekhon. This low-frequency noise, also known as Brownian noise, is named after Robert Brown , who documented the motion of inanimate particles in water (Brownian motion). This frequency is even lower than pink noise, mimicking rainforest soundscapes. Brown noise is also another name for red noise, since brown actually refers to Robert Brown and not the color brown.

Brown noise for sleep

There is little research supporting that brown noise actually helps with sleep, but it has been anecdotally used to improve focus, particularly for those with ADHD. One study published in bioRxiv suggests that beta-range frequencies, which are present in brown noise, can improve cognitive function, but research on how brown noise can improve sleep is minimal.

What are the other types of noise?

There's a wide spectrum of noise colors. Some of the most commonly named besides pink, brown and white are:

• Blue noise:Steady sound with higher frequencies, like the sound of a strong spray of water.

• Green noise:A more ambient sound with a variety of frequencies, closely associated with true-to-life nature sounds, like birds chirping in the distance or the sound of a waterfall.

• Gray noise:Very similar to white noise, gray noise gives every frequency an equal perceived loudness, to sound smoother and less hisslike, more like wind blowing.

• Black noise:Ironically, black noise is the complete absence of noise. Random sounds may appear, but at an extremely low frequency.

Is white, pink or brown noise better for sleep?

Before you search for the next great sleep playlist, there's little research to support that any of these sounds actually put you to sleep or make you stay asleep.

"From a sleep perspective, currently there is no major difference between these types of noises," says Dr. Swetha Gogineni , a pulmonologist board-certified in sleep medicine at Santa Monica Pulmonary Sleep Clinic in California. "Studies are limited and based off of current research, there's no strong evidence to support the use of these noises to promote different stages of sleep, but there are also no adverse effects with these noises."

That doesn't mean you should throw out your white noise generator . If background sounds like colored noise genuinely make you feel relaxed and comfortable before bed, there's no harm in using them to help you fall asleep — just don't expect them to be a cure-all for any recurring sleep issues.

"Ultimately, if you need to listen to a sound or a noise to help you fall asleep, you should pick the one that works best for you," says Gogineni.

FAQs

Is it safe to sleep with sound at night?

Yes, it is safe to sleep with sound at night, but noises that are too loud (85 dB and above) can lead to hearing loss, and sounds at roughly 60 dB could disturb babies and potentially lead to developmental delays . Be careful about the volume of the sounds you listen to.

Can noise help with insomnia?

Since the research is limited on whether noise can actually induce or maintain sleep, colored noise can be used as a relaxation aid to help prepare the body for sleep. However, if you're dealing with recurring sleep issues, it's better to address the underlying cause, like stress, anxiety or sleep apnea, by talking to your doctor.

Are there risks to using white, brown or pink noise long-term?

White, brown or pink noise is safe to use long-term as long as the sounds are at a reasonable noise level and not so close to the ear as to cause hearing damage. Always practice caution with any level of noise, whether it's white noise or your favorite music. "See what soothes you and what you feel better with," says Sekhon.

Meet the experts

• Anupamjeet Sekhon , MD, sleep and family medicine physician at Kaiser Permanente in Southern California

• Swetha Gogineni , MD, pulmonologist board-certified in sleep medicine at Santa Monica Pulmonary Sleep Clinic in California

Our health content is for informational purposes only and is not intended as professional medical advice. Consult a medical professional on questions about your health.