Is it safe to play a white noise machine all night long?

I have been using a white noise machine since my son was born. It helps him sleep. Is it wrong? Could this affect his hearing?

Many American households use white noise machines to help their children fall asleep and stay asleep. White noise is made up of different frequencies, creating a background sound that can muffle potential interference. The devices are easy to use, often in the form of a stand-alone machine or a smartphone application. The positives of this seemingly low-risk intervention are obvious: better sleep.

But how low is this risk? To find out, we conducted a review of the available literature on white noise machines for young children. The results, recently published in the journal Sleep Medicine, showed that all devices tested produced disturbingly loud sounds.

There is no uniform standard for exposure to noise from consumer products such as white noise machines. However, for workplace noise, the National Institute for Occupational Safety and Health (NIOSH) recommends limiting exposure to less than 85 decibels in eight hours and 82 decibels in 16 hours. That’s about the same noise as a lawn mower for eight hours or standing near busy traffic for 16 hours.

A toddler can sleep 10 to 12 hours a day, but infants can sleep up to 16 hours throughout the day. In our review, we found that 24 white noise machines and six phone apps could all produce sound that violated NIOSH’s eight-hour work shift guidelines. Some white noise machines can reach a volume of 91 decibels – about the same level as a Metrorail train hurtling through the station at top speed.

Most parents probably don’t set the device to its loudest setting. However, this finding means that during typical sleep, a white noise machine set to maximum volume exposes children to noise that could cause permanent hearing loss.

Changing the sound type to musical, static, rumble or tones does not make the sound safer, but lowering the volume does. In general, you should set the volume of your white noise machine to the lowest volume that helps your baby fall asleep. We recommend keeping the volume at 60 decibels or less.

Can white noise machines damage your hearing?

Exposure to white noise near its maximum volume is harmful for many reasons. Loud, prolonged exposure to noise causes mechanical stress on the sensory hair cells of the inner ear, inflammatory damage to their supporting structures and damage to the nerve endings of hair cells. This causes the tiny, hair-like receptor proteins on their surface to break, causing cell death and the loss of supporting cells.

Our research builds on this to show that exposure to white noise in young children is of even greater concern due to its potential impact on physiological and social development. Animal models exposed to noise levels ranging from 60 to 80 decibels have shown stunted vocal development and delayed neuronal development in the auditory processing centers of the brain.

Similarly, studies of children near high ambient noise, such as traffic, train or airplane noise, have been linked to negative effects on sleep time, sleep disturbances, cognitive development, behavioral problems, reading proficiency, and even changes in brain imaging of areas related to development. language. .

What is a safe level for a white noise machine?

Within reasonable limits, white noise can help children – and parents – fall asleep without causing harm. We found research showing that white noise at 60 decibels or less – about the volume of a quiet conversation – was shown to reduce arousal at night, increase sleep time, and increase sleep efficiency (time spent in bed).

To check whether the volume of your white noise device is safe, you can purchase a decibel meter online or download an app on your smartphone. NIOSH has created a free app calibrated specifically for iPhones called the NIOSH Sound Level Meter (SLM) app.

Set the white noise machine to the volume level you usually use and place the decibel meter where your baby sleeps. Sound intensity should be well below 82 decibels.

Lt. Col. Isaac Erbele is deputy program director of Otolaryngology – Head and Neck Surgery at Brooke Army Medical Center in San Antonio. Captain Russell De Jong is a resident surgeon in the Department of Otolaryngology – Head and Neck Surgery at Brooke Army Medical Center in San Antonio. The views expressed herein are those of the authors and do not reflect the official policy or position of Brooke Army Medical Center, Wilford Hall Ambulatory Surgery Center, the Department of Defense, or any U.S. government agency.