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

It is common that white noise facilitates falling asleep and improves the quality of sleep. We checked whether this is a scientific data confirm.

On the benefits of white noise, including for children, write thematic publics, Media, Different technical publications And, of course, Manufacturers Accessories for sleeping. In many sources, including medical, separately emphasizes that white noise helps to fall asleep babies and even Relieves They are from colic. On marketplaces The number of devices producing white noise is calculated by dozens, if not hundreds.

White noise is soundIn which all the frequency of the sound spectrum available to a person (from approximately 20 Hz to 20,000 Hz) are represented equally intensively. By analogy with white light, which consists of all colors of the spectrum, white noise is a uniform combination of all sound frequencies, creating a constant homogeneous background. From the point of view of physics and signal processing, white noise is a random signal with a constant power density throughout the frequency of the frequency. This means that its amplitude (or intensity) does not depend on the frequency, which makes the spectrum of white noise “flat”. Such a noise is often compared with a “static” sound that is heard, for example, when tuning a radio at a bearing frequency without a signal.

However, the human ear hears white noise otherwise. Due to the fact that the auditory system perceives the frequency of Logarithmic scale, high frequencies seem louder than low, with the same energy Power. Therefore, for a person, white noise is a brighter and more hissing sound.

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

• Pink noise - contains all frequencies, but the power decreases by 3 dB with each increase in the octave, which makes the sound lower -frequency and soft, similar to the noise of the waterfall;
• Brown (or red) noise - even more displaced towards low frequencies, sounds deeper, resembles rain or shower noise;
• Green noise - enhances average frequencies, similar to the sounds of ocean waves or streams.

Sleep problems are extremely common. More than a third of adults all over the world experience Symptoms of insomnia, and up to 67% of the inhabitants of the planet report on sleep disturbances at least once in the night. According to survey Philips, which included more than 11,000 respondents in 12 countries, 62% of adults evaluate the quality of their sleep as unsatisfactory. Eight of ten of them want to improve their dream, but 60% of them have never turned to the doctors for help. 44% note that the quality of their sleep has deteriorated over the past five years. Listening to soothing tracks before going to bed practices 67% of respondents - this is the second most common method, first place (69%) divide the reading and viewing of TV.

One of the main threats of sleep and health as a whole - This is a night noise. Specialists warnthat sleep in conditions of noise can lead to an increase in the risk of developing cardiovascular diseases, primarily hypertension, mental disorders, including depression, various cognitive disorders and obesity. Night noise increases production injuries at work and reduces the expected life expectancy.

At the same time, the white noise, as scientists suggest, can reduce the pernicious effects of night noise. In 2021, specialists from the University of Cornell (USA) Offered A group of ten volunteers living in the busy quarters of New York, include white noise generators for a while. The quality of sleep was evaluated subjectively (with the help of the diaries that the participants in the experiment) and objectively (with the help of an actograph - a device that looks like a wristwatch and monitors a person’s motor activity during a night's rest, and therefore allows us to judge a depth of sleep). Both methods showed that the dream of volunteers improved - they fell asleep faster and woke up less often at night. Scientists explained such a change by the fact that the white noise “masked” the noise of the city. However, in addition to a too small sample, the study did not include the control group and was not blind - the participants knew that the generator would create sound waves that contribute to sleep, and, perhaps, in their case the placebo effect worked. 

IN experiment 2024, conducted by Chinese scientists, the control group was included. Researchers focused on sleep and psychological comfort in patients with schizophrenia. Half of the participants (106 people) received only pharmacological treatment, and the other half every night turned on white noise for two hours. After 12 weeks in the second group, falling asleep accelerated, the quality of sleep improved, and the level of anxiety and depression decreased. However, in this case, the study was not blind - the volunteers knew what sounds include them and for what.

At the same time, newborn could definitely not be subject to such cognitive distortions. IN experience 1990 40 babies were divided into two groups: one was turned on the white noise, but the second - no. 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 influence of audio stimulation on sleep. They were interested in not only white noise, but also pink, as well as tracks using both noise and music (under the general name “Multiauadio”). In total, 34 studies were included in the meta -analysis, 19 of them showed an improvement in sleep due to sound stimulation, and 15 did not find any effect. Of these 19 experiments, six showed the effectiveness of white noise, nine - pink and four more - the effects of Multiauadio. Scientists noted the heterogeneity of the research methodology: sounds were played at different volume and frequency, either headphones or a generator were used, the sound was compared with silence, background noise (some studies were conducted in hospitals and nursing houses) and even with the wearing of Birusha and sleeping for sleeping. Therefore, as researchers concluded, the existing data is not enough to talk about some benefits. However, experts noted, and there were no side effects, so there is nothing wrong with listening to white noise, if you want.

At the same time, Sogard Medical School, Sogol Javaheri, He thinksWhat to talk about the safety of white noise is premature-it can interfere with such an important stage of sleep as a REM-fasa. This is a phase of quick sleep, necessary for the brain to restore and memorize information. Especially the REM-FAZ Important for newborn, since it is during it occur The main stages of the formation of the nervous system. 

The fears of Dr. Javaheri confirms Meta analysis of the influence of white noise on the early development of children, conducted in 2024. American researchers summed up experiments conducted on animals and during observation of children, and suggested that the constant effect of white noise during sleep could damage both cognitive functions and hearing. Observation of children who have undergone the chronic impact of white noise showed that they often had sleep disturbances, cognitive development slowed down, the number of behavioral problems increased, the volume of brain structures responsible for the development of speech, and the rate of teaching learning worsened. 

Scientists also alerted that white noise generators could be too loud - the examined devices are able to issue a sound level of more than 91 dB. This higher Even the maximum threshold values ​​recommended by the National Institute of Security and Labor Hygiene - and not for children, but for adults at the workplace.

The most fears of scientists were caused by applications for smartphones with white noise generation, since their maximum volume is limited only by the power of the dynamics of the device. At the same time, the generators of very quiet white noise with a short effect, probably, can contribute to falling asleep. Scientists conclude that resorting to white noise should be caused until more data has been obtained about the safe level of its impact on the development of infants.

Finally, another systematic analysis of white noise studies Spent Specialists from the Perelman Medical School at the University of Pennsylvania. They included 38 studies on how this sound affects the speed of falling asleep, the frequency of awakening, the depth of sleep and its duration. As experts considered, all these studies had a low level of evidence and a high level of bias. The sample turned out to be 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. Probably, white noise really helps people suffering from tinnitus (constant ringing in the ears) and patients in hospitals forced to try to sleep in unusual conditions. For adults and children sleeping at home in their bedrooms, white noise may only allow to mask the sharp sounds of traffic outside the window. However, evidence of even this ability in research is not enough. Scientists also pay attention to the fact that turning white noise is worth it with caution, since evidence of its complete safety is also not enough.

Thus, although there are a lot of research of white noise, they are all of poor quality and do not allow us to draw unequivocal conclusions about the usefulness of such a sound for falling asleep or improving the quality of sleep, or even about its safety. The use of white noise for sleeping babies is especially worried-presumably, a long sound exposure during sleep interferes with the REM-phase, which can cause cognitive impairment in children. Moreover, specialists are worried about the volume of white noise generators and relevant applications. At the same time, probably adults, subject to a small volume, white noise may seem peaceful and contribute to sleep, although, perhaps, this will be caused only by the placebo effect.

Image on the cover: Image by Claudio Scot from Pixabay

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