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Never have so many people been so interested in something so seemingly basic: sleep.
From the scientists and doctors who’ve collectively determined a good night’s sleep is critical to one’s health; to the consumers snapping up all forms of sleep technology (such as the 250-plus “white noise” apps available through the Google Play store); to the mattress designers, sleep aid manufacturers, pharmaceutical companies, and others creating solutions so people can sleep better. All told, according to research firm Statista, the global sleep economy will reach $488 billion in 2021 and grow to $585 billion by 2024—a whopping 20 percent increase in only three years.
Within the sleep economy, there are those who are focused on a seemingly basic reason that sleep eludes so many people: noise.
Noise awakens us (or keeps us awake), impacts our sleep stages, triggers excess adrenaline, and can elevate heart rates. It doesn’t necessarily take a scientist to understand that the snoring of a roommate, spouse, or significant other can prevent a good night’s sleep. Or that traffic, sirens, impolite neighbors, AC systems, you name it, can cause us to stir. But to what end? Many experts have detailed the health consequences of sleep disruption. Researchers have even studied the effect of night noise on the circadian rhythms of mice and hypothesized sensitivity to noise could disrupt human circadian rhythms, too.
In a nutshell, sleep is good. And noise is bad for sleep.
A Global Problem of Noise-Induced Sleeplessness
In fact, the impact of noise on sleep is a growing concern for societies all over the world. There have been extensive studies on the effect of aviation noise on people who live near airports. The same for sleep disturbance caused by trains. And as the world starts to address climate change in earnest, including by generating energy using wind turbines, there have even been studies exploring whether the subtle but constant noise from wind farms could affect the sleep of people who live near them.
In 2009, the World Health Organization (WHO) published “Night Noise Guidelines for Europe” with the aim of creating “health-based” guidelines for local jurisdictions to address “exposure to noise during sleep.” The WHO estimated that sleep disturbance caused by noise has reduced healthy life spans by a cumulative 900,000 years in Western Europe alone.
People are tired and it’s affecting their lives. Recently, the U.S. Centers for Disease Control (CDC) published a report that said one-third of adults were not getting enough sleep and that sleep deprivation was costing the country about $400 billion a year in lost productivity. The CDC called lack of sleep a “public health problem.”
In 2016, RAND Europe examined the economic burden of insufficient sleep across five different countries, citing along the way studies that showed how a lack of sleep is linked to health issues such as cardiovascular disease, hypertension, diabetes, and more. In fact, RAND estimated that the mortality rate for individuals who consistently get fewer than six hours of sleep per night is 13 percent higher than for those who sleep seven or more hours.
People need sleep for their health and wellbeing, which is why there are so many technology solutions to address myriad sleep-related issues, including noise.
Combatting Noise: Masking or Cancellation?
For all that goes into a $488 billion global sleep economy, fighting noise so people can sleep better has become an important area of innovation and inquiry. Among the key questions when trying to achieve quiet: Is it better to offset environmental noise through artificial means, or is it better to try and eliminate noise altogether? Noise masking, or noise cancellation?
Noise masking is the process of adding sound to a space so that it distracts from the sounds that cause people to lose sleep. This added sound is commonly referred to as white noise—a mix of all audible sound frequencies created to “mask” unwanted noise and promote. Alternately, there is pink noise, which amplifies certain frequencies and diminishes others. In either case, noise-masking calls for introducing one noise to help distract the brain from another. It can come from a special white noise device or smartphone app, a pair of earphones, or, depending on the situation and individual, from an everyday appliance like a fan.
But noise-masking may not be the best way to promote sleep. In a 2020 study by the University of Pennsylvania Perelman School of Medicine, “Noise as a sleep aid: A systematic review,” researchers wrote, “Introducing a continuous noise into the bedroom environment could potentially have negative consequences.” Because of how white noise works, it could mask sounds people need to hear, like a crying baby. If it’s too loud, white-nose could actually contribute to noise-induced hearing loss. And researchers concluded continuous white noise could hinder the deeper sleep levels people need to live healthier.
Most importantly, although some studies have shown that white noise can help people get to sleep faster, there is little evidence that it improves the quality of sleep. And quality sleep is healthy sleep.
In fact, there are some indications that continuous white noise exposure can negatively impact slow-wave (deep) and REM sleep. It’s in these latter stages of sleep when research indicates we derive the most health benefits—energy and cell restoration, strengthening of the immune system, and more. In other words, noise-masking may help put you to sleep but it can limit the benefits you get from that sleep because it may actually impair sleep during the healthful deep and REM sleep.
“It is conceivable,” the University of Pennsylvania researchers wrote, “that, much like the brain, the auditory system needs downtime to clear metabolic byproducts accumulated during waking hours.”
The Case for Cancellation
The alternative to masking noise in order to promote sleep is canceling it out. The same engineering principles applied to noise-canceling headphones, designed so people can enjoy music while filtering out ambient noise, like the drone of plane engines, can be applied to discrete earbuds designed for the sole purpose of creating silence and promoting sleep.
Such devices use what’s called active noise canceling (ANC) technology, which includes a tiny microphone to “hear” the ambient noise that might keep a person awake, and a tiny speaker that plays a phase-shifted version of the original ambient noise in order to cancel it out. They’re especially good at eliminating the kinds of low-frequency sound—snoring, traffic, voices, mechanical systems—that typically hinder sleep.
And because they’re purpose-designed to cancel noise—not to also process and amplify music or accept phone calls—they can be smaller than other earbuds, meaning they can be worn comfortably throughout a good night’s sleep. When combined with passive noise cancellation—form-fitting memory foam around the earbud that adds extra blocking of higher-frequency sounds—today’s discrete, miniaturized ANC technology offers the most complete solution for preventing noise and promoting the silence that studies have shown people need for a full night’s sleep.
These days, there is some momentum behind noise masking to improve sleep, and many noise-masking solution providers emphasize their effectiveness in helping people fall asleep. But as the emerging research indicates, falling asleep amid noise and staying asleep are two very different things. And staying asleep so that the body can reap the health benefits we know come from deep and REM sleep, can be better achieved by canceling out noise altogether.
When it comes to healthy sleep performance, silence is golden.
By Janne Kyllönen, Founder and Chief Product Officer at QuietOn
Janne Kyllönen is a founder and chief product officer at QuietOn. With a background as a physicist, Janne is a technological expert and uses his extensive background to drive product creation and improve user experience. Janne aims to create technology that makes life better. Before co-founding QuietOn, Janne worked at Nokia and Microsoft.