Are White Noise Machines Bad? Here's What the Latest Science Says

White noise is a constant, uniform sound that combines all audible frequencies simultaneously. A fan running, steady rain, television static, or the sound of a white noise machine are all examples of this type of sound.

Many people use white noise as a sleep aid to mask distracting sounds and help them fall asleep and sleep longer, especially for infants and children. However, some studies have shown that white noise can improve sleep quality,^One There are some potential downsides to be aware of.

White noise machines can damage children's hearing and cognitive development.

According to a study published in the Journal of Sleep Medicine, many white noise machines can be dangerously loud.² They are often used as sleep aids for infants and young children, but their maximum volume is not regulated, reaching levels that can pose risks to auditory and cognitive development.

The National Institute for Occupational Safety and Health (NIOSH) recommends an exposure limit of 85 decibels for an 8-hour shift and 82 decibels for a 16-hour shift.^three Lawn mowers, vacuum cleaners, and power tools are some of the machines that produce noise levels of around 85 to 90 decibels.

However, in a review of 20 studies, researchers found that white noise machines at maximum volume can produce levels higher than 91 decibels (dB), which exceeds the NIOSH safety guidelines for a two-hour work shift for adults. Additionally, all 24 white noise machines and six phone apps evaluated were capable of producing noise levels that exceeded the NIOSH guidelines for an eight-hour work shift.

“Most parents probably don’t set their machines on their loudest setting,” study authors Dr. Isaac Erbele and Dr. Russell De Jong wrote in The Washington Post. “But these findings suggest that playing white noise machines at full volume during a typical night’s sleep exposes children to noise that could cause permanent hearing loss.”⁴

Studies have shown that prolonged exposure to moderate-intensity white noise has been associated with negative early developmental effects in animal studies, suggesting that humans may be similarly affected. While some studies suggest that low-intensity noise exposure may be beneficial during sleep, the researchers concluded that “caregivers should avoid exposing their children to loud or prolonged white noise.” They added:

“Apps are potentially the most dangerous because they are governed by the maximum output of the phone hardware, which can reach up to around 100 dB. These standards are set for adults, but since there is no comparable scale specifically for this age group, they are used as a surrogate marker for hazardous noise levels in children and infants.

Moreover, since these devices are commonly used in young children who have long sleep times (e.g., more than 10 hours), the potential negative developmental impacts of long-term noise exposure may be magnified.”

Are white noise machines more likely to do more harm than good?

Another study, a systematic review published in Sleep Medicine Reviews, also found that the use of noise as a sleep aid may be overestimated and potentially harmful. The review found only very low-quality evidence that continuous noise improves sleep.⁵

“Conventional wisdom holds that continuous noise, such as from a so-called 'white noise machine', can improve sleep. A systematic review of the published scientific literature concluded that the quality of the evidence supporting this claim is very low.

“Continuous noise tended to reduce sleep onset latency (the time it takes to fall asleep) and sleep fragmentation (the amount of sleep interrupted during the night). However, the effects were not significant or statistically significant.”

Another study of premature infants in a neonatal intensive care unit suggested that white noise offered a “practical and potentially useful treatment” by reducing pain levels, heart rate, and respiratory rate, and promoting weight gain in infants.⁶ This may be a unique case where white noise makes sense, as it helps reduce pain levels, which are considered the biggest risk factor for long-term neurodevelopment in premature infants.⁷

However, in a typical home bedroom, rather than a noisy hospital environment, the risks may outweigh the benefits. Even low-frequency noise exposure, including the hum of an air conditioner, the low pitch of music, and thunder, can negatively affect higher-order cognitive functions such as logical reasoning, mathematical calculations, and data processing.⁸

Exposing infants and children to white noise for hours every night, explains neuroscientist Dr. Edward Chang:⁹

“I think there's a cost. You know, think about it a little bit. We're not naturally exposed to constant white noise… There's actually value in having really salient, structured sounds that are part of our natural environment, to how the brain develops normally. So, it's not clear whether that has an effect on how you sleep. I don't think any such studies have been done.”

The health risks of noise pollution are well established

Noise pollution is the presence of excessive or unwanted sound that disturbs the environment and negatively affects human health and quality of life. This often overlooked form of environmental pollution comes from a variety of sources, including traffic, industrial machinery, construction work, loud music, and even household appliances. The health effects can be significant, from hearing loss and sleep disturbances to increased stress, anxiety, and cardiovascular problems.

It is estimated that 10 million Americans have permanent hearing loss due to noise pollution or noise-related trauma.¹⁰ Beyond human health, noise pollution disrupts wildlife behavior and ecosystems, affecting animal communication, behavior, and reproduction.¹¹

Exposure to loud noises, including noise pollution, also contributes to hearing loss over time. The PLOS Biology team explained that lifetime exposure to loud noises can both worsen and trigger age-related hearing loss. “Presbycusis (age-related hearing loss) is a mixture of acquired auditory stress, trauma, and otologic disease added to the inherent aging process, due to the high levels of noise exposure in modern society.”¹²

Unsafe listening practices among teenagers, such as using personal listening devices (earbuds) or going to noisy places, increase the risk of hearing loss, which one study estimates could affect more than 1 billion people worldwide between the ages of 12 and 34.¹³

In New Jersey, one in 20 heart attacks may be caused by noise.

Living near a busy freeway or airport isn’t just annoying; it can also put your heart health at risk due to the noise levels. In fact, one in 20 heart attacks in New Jersey is attributed to noise from nearby freeways, trains, or air traffic, according to a study presented at the 71st Annual Scientific Session of the American College of Cardiology.¹⁴

In this study, patients hospitalized for heart attacks were divided into two groups. One group experienced high levels of traffic noise, defined as an average of 65 dB per day, and the other group experienced low levels of less than 50 dB per day. Results showed that 5% of heart attack hospitalizations were due to high noise levels, and the incidence of heart attacks was 72% higher in areas with high traffic noise.

The study authors suggested that some of the increased risk may be due to increased levels of air pollution in the area, as “air pollution and noise are closely linked,” but that noise may also cause chronic stress and sleep disturbances that affect cardiovascular health.¹⁵ A study published in Circulation Research suggests that cognitive responses to noise pollution may affect endocrine balance by causing excessive production of stress hormones.¹⁶

“Noise activates the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, which leads to the secretion of stress hormones such as cortisol and catecholamines,” the researchers explained.¹⁷ Chronic stress also promotes the secretion of cortisol, which strongly inhibits mitochondrial function and biogenesis.

If you use white noise, it will be safer if you do this:

Those who choose to use white noise at night should keep the volume low. Don’t turn it up to maximum. According to Sleep Medicine researchers:¹⁸

“White noise, within reasonable limits, can help children and their parents sleep without harm. We found studies showing that applying white noise at levels below 60 decibels (the volume of a quiet conversation) reduced nocturnal awakenings, increased sleep time, and increased sleep efficiency (the amount of time spent asleep in bed).”

You can use a decibel meter or sound level app to check the sound level of your white noise machine to make sure it is not at an unsafe volume. Turn on the white noise machine and place the decibel meter where you or your child sleeps to get an accurate reading. In general, the noise machine should be at least 7 feet away from where you sleep.¹⁹

If you or your children want to completely remove themselves from the noisy machine, gradually lower the volume until it is no longer needed.²⁰

Tips for protecting your health from noise pollution

Long-term exposure to high noise levels can have cumulative health effects, so it’s important to take action to protect yourself. If you’re concerned about noise levels in your area, consider talking to your local authorities or getting involved in community initiatives to address noise pollution. In the meantime, there are some practical steps you can take to protect your health from noise pollution.