White Noise – Definitions, Types and Impact on Sleep

Insomnia or difficulty in sleeping is one of the most prevalent problems, causing distress or impairment of normal functioning of the human body and mind. Insomnia can present itself as a sole disorder or can co-occur with other health issues.¹

Approximately 10-30% of the population is affected every year with sleeping difficulties.² Several behavioral and pharmacological methods have been implicated for the management of sleep difficulties.

For years, studies have reported that practicing proper sleep hygiene, a sleep-inducive calm environment, comfortable mattress and pillows help in improving the quantity and quality of sleep. In young children and adults, research has also indicated that non-pharmacological approach of using white noise as a method to induce sleep helps in improving sleep and reducing night-walking behaviours.³

This article mainly explains what white noise is, its benefits, how is it different from pink noise and devices that can be used to produce white noise.

What is white noise?

A white noise is defined as the noise whose power is independent of the frequency. White light is described as the light composed of every visible wavelength on the color spectrum, similarly white noise consists of every audible frequency at same intensity.⁴

Stochastic resonance, is the phenomenon, where signals are enhanced with the addition of random noise. The phenomenon in which the perception of one sound is masked or reduced by another sound is known as the auditory masking. A white noise is an example of stochastic resonance used for masking.⁵ It is a noise that is made up of low medium and high frequencies played at the same levels of intensities. The white noise makes hearing threshold level to its maximum, which causes intense stimulation of the auditory senses causing less perception by brain and masking other environmental sounds in the background.⁶

Sound machine:

A white noise machine is also known as sound machine. It helps in creating more calming environment for the onset and stability of sleep that promotes better health and performance at work. Several types of compact user friendly sound machines are available in market with multiple in built functions such as alarm, looping, timer with various settings to produce different colors of acoustic noise. Now a days, you can easily download a white noise application on your smart phone or tablet. Several apps are available, they are user friendly and inexpensive.⁴

Various colors of noise:

White noise has been considered similar to various environmental sounds, it should be kept in mind that their effect on sleep and mind may be similar, but white noise must consist of all audible frequencies played randomly at the same amplitude.

White noise is commonly compared and confused with several other sounds that are actually different colors of noise. A common example of calming colored sound is pink noise. White noise consists of all audible frequencies played randomly at equal intensities, on the other hand in pink noise with every increase in frequency the amplitude decreases by half that creates a mixture of more intense low-frequency tones and softer high-frequency tones.⁷

Similar to pink noise, the intensity of red noise also decreases with increase in frequency. Red noise consists of a low rumbling sound. Human ear is particularly more delicate towards rising frequency; hence many people find pink noise more pleasant than white noise. Several studies have reported that pink noise can actually reduce the activity in brain waves that causes reduced activity in brain during the initial stages of sleep, thereby assisting in sleep onset, increasing the duration of sleep, and improve overall quality of sleep. Pink noise has also been reported to improve the memory and performance.

People who prefer pink noise may also find red noise calming. At the end, the best color of noise for sleep will come down to individual preference. It is recommended to experiment with different colors of noise using a sound machine.

Benefits of white noise

• Helps in inducing sleep for hospitalized patients in critical and intensive care units⁶
• Helps in improving the perception of sensory activity, cognitive functions and memory⁸
• Helps children with attention deficit problems
• Helps in improving word learning and attentive skills in young adults⁵

 Conclusion

Insomnia is one of the leading health issues of modern tech-savvy generation. Decreased quantity and quality of sleep at night can lead to several health disorders including increased daytime sleepiness and reduced cognitive performance. Various behavioral modifications have been implicated to manage insomnia such as following a proper sleep hygiene, sleeping in comfortable, ambient environment with minimum disturbance from environmental and traffic sounds. White noise or sound machines present a user friendly and inexpensive method of masking external unnecessary sounds hence improving quality and quantity of sleep.

FAQ’s

Q1. Is it ok to play white noise all night?

A1. It is not advisable to use white noise all night long. Hearing normal home and environmental sound helps in understanding and getting used to the interesting sounds around like speech and music.

Q2. Is it better to sleep in noise or in silence?

A2. Sleeping in complete silence could be difficult for some people. Sleeping in a steady consistent background noise can help to mask different sounds that might keep you awake during the night.

Q3. Can it be harmful to use white noise?

A3. Using white noise for longer periods can cause hearing problems and increased risk of development issues in babies.

Q4. Effect of sound machine on the development of baby?

A4. Exposure to continuous use of sound machine can cause hearing impairment as well as problems with development of speech and cognitive functioning.

Q5. Where should i keep sound machine in my room?

A5. The most appropriate place to keep sound machine is near your bed or on the bed side table.

Q6. Can sound machines cause deafness?

A6. It is important to choose right sound machine for undisturbed sleep. excessively loud sound machines can cause hearing problems. It is recommended to use machines that produce around 50dB noise.

Q7. Which color noise is better for babies?

A7. Pink noise is a low frequency sound and is considered more soothing for babies than white noise. It helps the baby to fall into deeper and longer sleep. Studies suggest that pink sleep also helps in improving short and long-term memory.

References

1. Harvey AG, Tang NK. (Mis)perception of sleep in insomnia: a puzzle and a resolution. Psychol Bull. 2012;138(1):77-101. doi:10.1037/a0025730
2. Maness DL, Khan M. Nonpharmacologic Management of Chronic Insomnia. Am Fam Physician. 2015;15;92(12):1058-64. https://pubmed.ncbi.nlm.nih.gov/26760592/
3. Riva MA, Cimino V, Sanchirico S. Gian Lorenzo Bernini’s 17th century white noise machine. Lancet Neurol. 2017;16(10):776. doi: 10.1016/S1474-4422(17)30297-1.
4. Riedy SM, Smith MG, Rocha S, Basner M. Noise as a sleep aid: A systematic review. Sleep Med Rev. 2020;55: 101385. doi: 10.1016/j.smrv.2020.101385.
5. Angwin AJ, Wilson WJ, Arnott WL, Signorini A, Barry RJ, Copland DA. White noise enhances new-word learning in healthy adults. Sci Rep. 2017;7(1):13045. doi: 10.1038/s41598-017-13383-3.
6. Farokhnezhad Afshar P, Bahramnezhad F, Asgari P, Shiri M. Effect of White Noise on Sleep in Patients Admitted to a Coronary Care. J Caring Sci. 2016;5(2):103-109. doi:10.15171/jcs.2016.011
7. Zhou J, Liu D, Li X, Ma J, Zhang J, Fang J. Pink noise: effect on complexity synchronization of brain activity and sleep consolidation. J Theor Biol. 2012; 306:68-72. doi: 10.1016/j.jtbi.2012.04.006.
8. Herweg NA, Bunzeck N. Differential effects of white noise in cognitive and perceptual tasks. Front Psychol. 2015;6: 1639. doi: 10.3389/fpsyg.2015.01639.