Is it true that white noise helps you fall asleep and improves your sleep?

It is widely believed that white noise makes it easier to fall asleep and improves sleep quality. We checked whether scientific evidence supports this.

About the benefits of white noise, including for children, write thematic publics, Media, various technical publications and, of course, manufacturers accessories for sleep. In many sources, including medical, it is separately emphasized that white noise helps infants fall asleep and even relieves them from colic. On marketplaces The number of devices that produce white noise is in the tens, if not hundreds.

White noise is sound, in which all frequencies of the sound spectrum accessible to humans (from approximately 20 Hz to 20,000 Hz) are equally intense. Similar to white light, which consists of all the colors of the spectrum, white noise is an even combination of all sound frequencies, creating a constant, uniform background. From a physics and signal processing perspective, white noise is a random signal with a constant power density across the entire frequency range. This means that its amplitude (or intensity) is independent of frequency, making the spectrum of white noise "flat". This noise is often compared to the "static" sound that is heard, for example, when a radio is tuned to a carrier frequency with no signal.

However, the human ear hears white noise otherwise. Due to the fact that the auditory system perceives frequencies according to logarithmic scale, high frequencies seem louder than low frequencies for the same energy power. Therefore, for humans, white noise is a brighter and hissing sound.

White noise is just one of several types of noise that differ in their energy distribution across the frequency spectrum. Other types of noise include:

• pink noise - contains all frequencies, but the power decreases by 3 dB with each octave increase, which makes the sound more low-frequency and soft, similar to the noise of a waterfall;
• brown (or red) noise - even more shifted towards low frequencies, sounds deeper, reminiscent of rain or shower noise;
• green noise - enhances mid frequencies, similar to the sounds of ocean waves or a stream.

Sleep problems are extremely common. More than a third of adults worldwide experience symptoms of insomnia, and up to 67% of the world's population report sleep disturbances at least once a night. According to survey Philips, which included more than 11,000 respondents in 12 countries, 62% of adults rated their sleep quality as unsatisfactory. Eight out of ten of them want to improve their sleep, but 60% of them have never sought help from a doctor. 44% say their sleep quality has worsened over the past five years. Listening to soothing tracks before bed is practiced by 67% of respondents - this is the second most common method, first place (69%) is shared by reading and watching TV.

One of the main threats to sleep and overall health - This is a night noise. Specialists warnthat sleeping in noise can lead to an increased risk of developing cardiovascular diseases, primarily hypertension, mental disorders, including depression, various cognitive disorders and obesity. Night noise increases occupational injuries and reduces life expectancy.

However, white noise, as scientists suggest, can reduce the harmful effects of night noise. In 2021, specialists from Cornell University (USA) offered a group of ten volunteers living in busy New York City neighborhoods turned on white noise generators while they slept. The quality of sleep was assessed subjectively (using diaries kept by the participants in the experiment) and objectively (using an actigraph, a device that looks like a wristwatch and tracks a person’s motor activity during the night’s rest, and therefore allows one to judge the depth of sleep). Both methods showed that the volunteers' sleep improved - they fell asleep faster and woke up less often at night. Scientists explained this change by saying that the white noise “masked” the noise of the city. However, in addition to having too small a sample, the study did not include a control group and was not blinded—participants knew that the generator would produce sound waves to promote sleep, and the placebo effect may have worked in their case. 

IN experiment 2024, conducted by Chinese scientists, included a control group. Researchers focused on problems with sleep and psychological comfort in patients with schizophrenia. Half of the participants (106 people) received only pharmacological treatment, and the other half were exposed to white noise for two hours every night. After 12 weeks, the second group fell asleep faster, sleep quality improved, and levels of anxiety and depression decreased. However, in this case, the study was not blind - the volunteers knew what sounds they were playing and why.

However, newborns certainly could not be subject to such cognitive distortions. IN experience In 1990, 40 infants were divided into two groups: one was exposed to white noise, and the other was not. In 5 min. in the first group, 80% of the subjects (16 children) fell asleep, and in the second - only 25% (five).

American scientists tried conduct a meta-analysis of existing studies on the effects of audio stimulation on sleep. They were interested not only in white noise, but also in pink noise, as well as tracks using both noise and music (collectively called “multi-audio”). A total of 34 studies were included in the meta-analysis, 19 of which showed improved sleep in association with sound stimulation, and 15 found no effect. Of these 19 experiments, six showed the effectiveness of white noise, nine showed the effectiveness of pink noise, and another four showed the effects of multi-audio. Scientists noted the heterogeneity of the research methodology: sounds were played at different volumes and frequencies, headphones or a generator were used, the sound was compared with silence, with background noise (some studies were conducted in hospitals and nursing homes) and even with wearing earplugs and a sleep bandage. Therefore, as the researchers concluded, the existing evidence is insufficient to suggest any benefit. However, experts noted, no side effects were identified, so there is nothing wrong with listening to white noise if you want.

At the same time, Sogol Javaheri, a somnologist from Harvard Medical School believesIt’s premature to talk about the safety of white noise - it can interfere with such an important stage of sleep as the REM phase. This is the phase of REM sleep necessary for the brain to recover and remember information. Especially the REM phase important for newborns, since it is during this are happening the main stages of the formation of the nervous system. 

Dr. Javaheri's concerns confirms meta-analysis of the effect of white noise on early childhood development, conducted in 2024. American researchers summarized experiments conducted on animals and while observing children, and suggested that constant exposure to white noise during sleep can damage both cognitive function and hearing. Observation of children exposed to chronic white noise showed that they had more sleep disturbances, slowed cognitive development, increased the number of behavioral problems, decreased the volume of brain structures responsible for speech development, and deteriorated the speed of learning to read. 

Scientists were also concerned that white noise generators could be too loud - the devices studied were capable of producing sound levels of more than 91 dB. This higher even the maximum thresholds recommended by the National Institute for Occupational Safety and Health—and not for children, but for adults in the workplace.

The scientists' greatest concerns were caused by applications for smartphones that generate white noise, since their maximum volume is limited only by the strength of the device's speakers. However, very quiet white noise generators with short-term exposure can probably promote sleep. Scientists conclude that white noise should be used with caution until more data is available on its safe levels of exposure to infant development.

Finally, another systematic analysis of white noise research held specialists from the Perelman School of Medicine at the University of Pennsylvania. They included 38 studies on how this sound affects the speed of falling asleep, the frequency of awakenings, the depth of sleep and its duration. According to experts, all of these studies had a low level of evidence and a high level of bias. The samples were small (more than half of the studies included up to ten subjects), the results were not statistically significant, and the design did not take into account either control groups or blindness participants. It is likely that white noise actually helps people who suffer from tinnitus (a constant ringing in the ears) and hospital patients who are forced to try to sleep in unusual conditions to fall asleep. For adults and children sleeping in their bedrooms at home, white noise may only mask the harsh sounds of traffic outside the window. However, research evidence of even this ability is insufficient. Scientists also point out that white noise should be used with caution, as evidence of its complete safety is also lacking.

Thus, although there are many studies of white noise, they are all of low quality and do not allow us to draw clear conclusions about the usefulness of such a sound for falling asleep or improving sleep quality, or even about its safety. Scientists are especially concerned about the use of white noise for infants' sleep - presumably, long-term sound exposure during sleep interferes with the REM phase, which can cause cognitive impairment in children. Moreover, experts are concerned about the volume of both white noise generators and related applications. At the same time, it is likely that adults, at low volume, may find white noise calming and promote sleep, although this may be due only to the placebo effect.

Cover image: Image by Claudio Scot from Pixabay

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