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2024年10月3日

What Is White Noise? Sleep Benefits Explained

  • What Is White Noise?
  • Potential Benefits
  • How to Start with White Noise
  • Other Tips for Quality Sleep

Can’t sleep? If that’s the case, you’re not alone. Luckily, there are things like white noise generators that could help.

Millions of adults – and children and babies, too – struggle to get enough sleep each night, due to issues like stress, chronic pain, sleep apnea and even normal development. Thankfully, some simple sleep aids have been shown to help, including the use of soothing sounds, such as white noise (and other noise “colors” too).

What Is White Noise?

All sound waves can be broken down into two categories: frequency, or how fast the waveform is vibrating per second, and amplitude (or “power”).

White noise is defined as noise that contains a mixture of all audible frequencies that human ears can hear (about 20 hertz to 20 kilohertz). This type of noise includes low-, midrange- and high-frequency sounds. 

Some noise types (or colors) get their names based on colors of light wavelengths. White light contains all the frequencies in the visible range, so you can see how white noise earned its name. Another way to think about it is as “20,000 tones all playing at the same time.”

There’s somewhat of a misunderstanding about what qualifies as white noise exactly. For example, many believe that all static sounds (or “background noises” that mask other sounds) like those of an air conditioner, refrigerator or fan are types of white noise – but in reality, our environments are filled with a mix of white, pink and brown noises, among others.

So what are examples of white noise? Pure white noise is said to resemble a “hissy shhh” sound or the sound you hear if a TV or radio was tuned to an unused frequency.

According to an article published in The Atlantic, “In audio engineering, there’s a whole rainbow of noise colors, each with its own unique properties, that are used to produce music, help relaxation, and describe natural rhythms like the human heartbeat.”

Other colors are similar to white noise, but they sound a bit different because they are concentrated at either the high or low end of the sound spectrum.

Here’s a bit about the different types of noise colors:

White Noise vs. Pink Noise

Pink noise is white noise but with reduced intensity as the frequency rises. It’s described as being “less harsh” than white noise and a bit softer and more soothing, with more bass sounds.

If you find that white noise is a bit too intense for you, try pink noise instead. It may be perceived as more balanced and subtle.

Examples of pink noise that you’re probably familiar with include the sound of rainfall or ocean waves. Research also shows that pink noise can increase productivity and creativity, so it’s worth experimenting with.

White Noise vs. Brown Noise

Brown noise is a deeper version of pink noise, described as having bassy rumbles. Examples in everyday life include a strong wind, rumbles of ocean waves or a steady stream.

White Noise vs. Black Noise

Black noise is basically silence with a little bit of random noise thrown in. This is why it’s also sometimes called “technical silence.”

Technically black noise has a frequency spectrum of predominantly zero power level over all frequencies except for a few narrow bands or spikes.

Green noise is another type of white noise that describes nature sounds, like rustling leaves or a babbling brook.

Potential Benefits

What does white noise do to you? Below are some of the effects and benefits associated with white noise.

1. Can Help Improve Your Sleep

As of 2012, a National Sleep Foundation poll found that only 5 percent of Americans slept with a “sound conditioner” (a fancy name for a sound machine, app or even household device like a fan).

Why is it good to sleep with white noise? It can be an effective tool for “noise masking” and help avoid trouble sleeping.

Studies indicate that listening to white noise for sleep can have some payoffs, such as by blocking out other sounds that can startle you out of sleep. That said, some research suggests pink noise may be even better for sleep.

If you use a white noise machine or app on your phone, such as to help you or your baby/child sleep more soundly, you likely listen to a continuous signal of mixed sounds played at a relatively low volume, rather than sounds that are too loud or seem choppy or interrupted. The sounds that sound machines generate are consistent and ambient, which allows them to help mask other distracting, startling and disturbing sounds.

Researchers believe that white noise is a noise that makes someone’s hearing threshold level reach its maximum rate, which means the presence sounds in the background become less capable of stimulating the cerebral cortex region of the brain during sleep.

Time magazine also reports that, according to sleep experts, “even if your bedroom is pin-drop quiet, sound machines can be helpful, if you’re the type of person unsettled by a total absence of noise, or if you’re a light sleeper who wakes from even the softest sound.”

A study published in 2021 examined the effects of white noise on sleep for 10 New York City residents who live in a high-noise environment. While the sample size is small, the data showed that “white noise significantly improved sleep based on subjective and objective measurements in subjects complaining of difficulty sleeping due to high levels of environmental noise.”

Further research confirms these findings. For instance, white noise helped improved average total sleep time in patients admitted to a coronary care unit in a 2016 study, while research published in 2022 found that critically ill patients improved their sleep quality with the use of white noise.

2. May Assist You When Studying and Working

A 2017 study published in Scientific Reports found that benefits of white noise for studying include enhanced learning of new information. Researchers concluded, “Research suggests listening to white noise may improve some aspects of cognitive performance in individuals with lower attention.”

This study investigated the impact of white noise on new word learning in healthy young adults. Half the participants listened to white noise during the learning phases, and half completed the learning in silence.

Results demonstrated that the white noise group experienced “enhanced lexical acquisition.” The researchers involved in the study also point out that in children with ADHD, listening to white noise has been shown to improve performance on memory tasks, as well as improve speech recognition.

Although it works for some people, white noise does not provide a general enhancement for all aspects of cognition, and it’s still unclear if it may actually decrease attention among certain people, such as those who focus best when working in silence. Overall, studies suggest there are differing effects on perception and cognition when white noise is used, which may depend on factors like specific task demands and timing.

3. Can Reduce Agitation and Stress

Certain studies have uncovered evidence that white noise can serve as a “simple, convenient, and noninvasive intervention that improves agitated behavior in older adults.” In one particular study, the use of sound machines was shown to improve the moods and behaviors of older adults living with dementia.

How to Start with White Noise

White sound machines are now widely available and come in a range of prices and specifications.

In order to test out several different types of sounds, you want to look for a machine that produces a range of noise “colors” (white, pink or brown) and is non-looping, so it plays continuously all night.

Another thing to consider is whether or not you need a portable, small machine (for example, if you travel a lot or bring it out with you to help your baby sleep) and whether you want a chargeable machine or one that needs to be plugged in.

There’s also the option to use a sleep/sound machine app on your phone if you don’t want to purchase a device. If using white noise while studying, try listening to YouTube videos on your computer or phone completely for free, which can play in the background and drown out other distracting sounds.

Is white noise harmful if you listen to it for too long or at a high volume? For most adults, there’s no harm in listening to noise colors while sleeping or focusing on a task.

According to the American Association of Pediatrics, while “infant sleep machines can be used to mask environmental noises in busy households or to provide ambient noise to soothe an infant during sleep,” some white noise machines intended for use with infants/babies may play at too high of a volume. Therefore, you should place the machine at least seven feet away from your baby’s crib, and avoid setting the machine to its maximum volume.

Other Tips for Quality Sleep

Aside from using a white noise machine to help you sleep more deeply, here are other natural sleep aids to try:

  • Maintain a regular sleep schedule so you go to sleep and get up at roughly the same time each day.
  • Stop using screens and electronics two or more hours before bed. This will prevent too much blue light exposure, which can keep you up.
  • Create a sleep-friendly environment in your bedroom by keeping it dark and slightly cool. Keeping your room organized and diffusing lavender or other essential oils for sleep can also make it feel calming.
  • Limit your consumption of caffeine after 12 p.m., since it can remain in your system for hours.
  • Try having a dinner or nighttime snack that includes “sleep-promoting foods,” such as those with complex carbs, calcium, magnesium and/or the amino acid tryptophan.
  • Consider trying herbal supplements that can help manage stress and support good sleep, such as valerian root or passion flower.
  • Practice sleep hygiene best practices.
  • Try ASMR.

Conclusion

  • What is white noise? It’s a type of noise that contains a mixture of all audible frequencies that human ears can hear (about 20 Hz to 20 kHz). It sounds like a hiss or “shhh” sound.
  • Examples of white noise that you’re probably familiar with include the sound of a TV or radio when set to an unused frequency.
  • While other noise colors may be more calming for certain people, white noise benefits can include promoting relaxation, sleep quality, and focus while studying and working.
  • You can start using “noise colors” by purchasing a white noise sound machine or using an app on your phone. You’ll probably have the best results if the noise plays continuously all night on a loop without breaks.
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