The Relationship Between Sound And Sleep

When we talk about the connection between sound and sleep, more often than not we’re talking about the negative impact. While it’s true that loud city hustle and bustle, noisy neighbors and even a snoring partner can be major impediments to sleep — there are some sounds that can actually be beneficial for rest. Not only can some soothing sounds help you fall asleep, but certain ones can even help you get deeper more quality shut-eye.

For some people, noise can be a major impediment for their sleep health—whether by preventing you from falling asleep or rousing you in the middle of the night. In some cases, a noisy environment may not be enough to fully wake you up but can still impede sleep quality and prevent you from moving into deeper REM sleep.

But not all nighttime sounds are the same. Whether you’re looking to drown out disruptive noises or trying to quiet an overactive mind, there are a number of ways to harness music and audio sounds to improve your sleep hygiene.

Relaxing Music & Lullabies

Listening to relaxing music is one of the most popular nighttime habits. More than simply creating a more soothing bedtime experience, music has been scientifically proven to have a direct impact on brain function. Studies show that listening to certain kinds of music can help slow your heart rate, lower your blood pressure and potentially even trigger your muscles to relax.

It’s why parents of newborns often sing to their babies to help coax them back to sleep. According to a study conducted by a doctoral student from the Université de Montréal, lullabies are an effective way to encourage sleep - in part because music can help regulate and stimulate certain emotions by triggering specific neural connections.

It has the same effect on adults as well. Different kinds of music can promote different reactions in people (think of an athlete listening to their favorite pump-up song before a race). Slow, relaxing music has been shown to quiet the nervous system, reduce stress and anxiety and promote the release of feel-good hormones such as serotonin and oxytocin. Because of these soothing effects, studies have shown that “relaxing classical music is an effective intervention in reducing sleeping problems.”

But is classical music the only type of sound therapy that will help you sleep? Not necessarily. Research suggests that the best kind of music to listen to before bed is one that has about 60 beats per minute, as this can trigger your brain to slow your heart rate down to that more relaxed rhythm. Any type of music that matches that beat—preferably one that has no defined melody and minimal volume changes—will work.

And while there are plenty of studies that show a connection between music and improved sleep, new research has pointed to other ways to generate those same effects. "Distracting your mind from whatever you would normally be thinking about and focusing on something specific and benign to relaxing (as one often does in meditation) can help set the stage for sleep," explained Professor Sean Drummond, director of the sleep and circadian rhythms theme at the Turner Institute for Brain and Mental Health within Monash University. "Nature sounds are used as 'white noise' machines and can help people block out the world and relax. [But] I do not know of any data evaluating whether they are any better or worse than any other kind of sound.”

Bed Time Stories

Another hold-over from childhood, the classic bedtime story is having a revival among sleep-deprived adults. Studies have shown that listening to a certain kind of audio story can similarly serve as a distraction for struggling sleepers. The key is finding the right one: the story should be long and quiet, full of sensory descriptions and devoid of much plot or narrative intrigue. These boring tales work by giving your brain just enough to focus on that it is distracted from the day-to-day worries that can wreak havoc on sleep—but not enough that it gets reenergized by following an exciting story. 

Casper recently did a round up of some of the best podcasts for sleep. The list includes a wide variety of different audio options: everything from bedtime stories like Sleep With Me to ambient sounds like the Deep Energy Podcast to the more traditional Classical Music Discoveries.

Other Sleep-Promoting Sound Therapies To Try

White Noise: By combining a variety of sound waves across a wide frequency range, white noise works by masking other more jarring or inconsistent noise during the night. White noise machines can help you fall asleep and stay asleep longer.

Pink Noise: Similar to white noise, pink noise combines a wide range of frequencies—but does so in a way that grants each octave equal power. This creates more evenly distributed sound waves, which sound more natural to the human ear. Though the research is still in the early stages, scientists have found that pink noise may significantly increase periods of deep slow wave sleep—which can have a positive impact on memory retention.

Binaural Beats: Like with pink noise, binaural beats utilize a process called entrainment - through which brainwave patterns are altered by exposure to certain sound wave frequencies. This kind of sound therapy requires headphones: the user hears sounds at slightly different frequencies in either ear. Science has shown that exposure to this type of variance in sound waves will prompt the brain to process and absorb a lower-frequency tone. That, in turn, slows down brainwave activity in a way that may help  lower anxiety, fall asleep faster and achieve more quality rest.

ASMR: A newly discovered phenomenon, ASMR stands for “autonomous sensory meridian response.” This sensory reaction can include an intensely pleasurable and relaxing tingling sensation in response to specific sounds or images, most commonly whispering, tapping or hand movements. While not everyone experiences ASMR, those that do have found it to be beneficial in treating insomnia and other sleep issues. According to a 2018 study among people who have ASMR, users experienced notable reductions in psychological and physical signs of stress after watching an ASMR video—including heart rate reduction. These calming effects can contribute to a better night sleep. 

Bone Conduction Sound Technology: This one has less to do with the qualities of the audio itself, and more to do with how it is communicated to the brain. When we hear any type of external noise, we are most often hearing it through “air conduction”—meaning the sound waves travel through the air and enter our outer ear. With “bone conduction,” the sound is transferred to your brain through vibrations within your skull and inner ear tissues. A good example of this technology being used for sleep purposes is from Dreampad Sleep. Studies have shown that this tech-savvy pillow can help activate the parasympathetic nervous system via the vagus nerve, which in turn helps regulate stress, minimize anxiety and promote relaxation. 

Even though science has proven that sound can have a direct impact on your mood and sleep, it’s not a one-size-fits-all solution. People have different reactions to different types of audio, based on their history and specific brain alchemy. As such, researchers suggest giving the various options a test run for a couple of days to see which one is most effective for you.

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This article originally appeared in Sleep Retailer eNews on July 11, 2019.

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