Our brains are hardwired to respond to sound. The powerful and diverse effects of sound can energize a workout or inspire a dance party. Certain sounds can also influence your body’s physiological responses. Slower-paced music, for instance, can have a calming effect on your nervous system, relaxing you and even helping you drift off at night.
Soothing sounds, such as a sound bath or color noises, like the brown noise of water, pink noise, or white noise, might also help calm you into sleep.
“When we introduce more ambient and nature-oriented sounds, there’s a natural calming effect because these types of sounds are not attempting to influence you in the same way that other music does,” says Nate Martinez, sound therapy practitioner and founder of NTM Sound. “With traditional music, there's emotional content, the tempo of a song, and other factors that can and do manipulate us.”
Research connecting sound and sleep has often focused on music — classical music in particular — showing that it benefits sleep patterns by reducing sympathetic nervous system activity — decreasing anxiety, blood pressure, heart and respiratory rate, as well as encouraging muscle relaxation. Studies suggest that music with lower frequencies, such as a strong base and slow and sustained musical notes, are best in helping people fall asleep. Of all the sounds known for encouraging relaxation, a favorite among sleep specialists is binaural beats.
What Are Binaural Beats?
Binaural beats are two tones with two frequencies, divided between your two ears (you need headphones or earbuds to experience them).
Binaural means having two aural devices — or two ears. Binaural beats are a sound that takes advantage of your two ears to transmit two sounds. When played together, they create an auditory illusion for your brain as it pulls together the sound of two different tones with different frequencies, one in each ear, combining them to create one low-frequency sound.
For instance, say you’re listening to a tone with a frequency of 130 hertz (Hz; the unit of measurement for sound frequency) in your left ear and a tone of 120 Hz in your right ear. Rather than hearing two different tones, your brain compensates by creating the perception of a new third tone equivalent to the difference between the two you’re playing. In this case, it would be 10 Hz. That third tone is called a binaural beat.
In order for your brain to process binaural beats, both tones you’re listening to need to be at frequencies less than 1000 Hz, and the difference between the two tones must be between 1 and 30 Hz.
The different frequencies of binaural beats are meant to correspond with five established categories of brain waves, or measurements of electrical activity among neurons, which are denoted by Greek letters. These, in turn, map to different mental states and activities. Theta waves, for instance, fall within around the 4- to 8-hertz range and are associated with deep relaxation; the buzzier gamma brain wave, at 30 hertz and higher, relates to stimulation and attention.
Though there isn’t a large volume of clinical science to support binaural beats, the idea behind binaural beats is that you can back yourself into a state of mind, in a sense, by playing the frequency associated with the mood you want. Your brain waves synchronize with the tone, and — at least in theory — your mental state then synchronizes with your brain waves.
Additionally, advocates say that the low-frequency tone of binaural beats can slow down brain activity similarly to meditation — and do it much more quickly, which may help lower anxiety and encourage relaxation. That makes it easier to fall asleep and sleep more soundly.
“When you remove certain elements that regularly exist in structured music, like melodic and rhythmic content, and instead are introduced to more drone-like sounds, it can allow the listener to have a more open-ended and often introspective experience,” Martinez says. “Without the melodic and rhythmic content, there is less information available to influence your experience,” so it becomes a calming, more meditative experience.
Do Binaural Beats Work?
To understand how binaural beats may help relaxation, mood, and sleep, it helps to understand a little bit about brain waves, says Dr. Brandon Peters, a sleep physician at Virginia Mason Medical Center. “Brain waves are produced by electrical impulses from neurons communicating with one another. Our thoughts, feelings, and actions are all expressed through this continuous neural communication, which means our brainwaves are associated with how we think, feel, and behave at any given moment.
Binaural beats can be created at different frequencies, each corresponding to a particular level/type of brain wave activity.
“It can be helpful to think about brainwaves as a wavelength or state of being, so if we want to downshift from a more active state to a more relaxed state, then ‘entraining’ or syncing to a specific brainwave range with the help of a binaural beat might be the answer,” Martinez says.
There are five main categories of brainwaves, though, for these purposes, we’ll consider the four that can be picked up by EEG.
Beta waves (ranging between 13 Hz and 30 Hz) are the pattern of normal waking consciousness and are associated with concentration, alertness, arousal, and cognition. At higher levels, the beta pattern is associated with anxiety.
Alpha patterns (8 - 13 Hz) indicate that we’re calm and relaxed yet still alert. Alpha waves reflect a state of relaxed wakefulness that can be achieved with meditation.
Theta pattern waves (4 Hz - 8 Hz) are common in lighter sleep stages, and also that fuzzy transition from wake to sleep, as well as deep meditation or relaxation.
The delta pattern (1.5 Hz - 4 Hz) is what happens in your brain during your deepest sleep stages.
Researchers have long observed that sound waves can affect brainwave patterns. Some studies suggest that listening to binaural beats can cause your brain waves to synchronize with the frequency set by the frequency of the beat. So essentially, you’re using binaural beats to reach a certain mental state. When the brain hears beats in low-frequency tones, those sound waves create shifts in brainwaves, generating slower frequency waves that promote a deeper state of relaxation.
One preliminary study found that binaural beats at a frequency of 3 Hz increased delta brain waves, which may encourage deep sleep. During sleep, the brain generates different types of brain waves depending on the sleep stage and the level of mental arousal. Low-frequency theta and delta brain waves are associated with relaxation and deep sleep. Binaural beats may help you sleep better by creating shifts toward theta and delta-type brain waves.
“When we can breathe and listen with greater focus and awareness, it can have a huge impact on our nervous system as well as our psyche,” Martinez says. “The end result is that we can feel more calm and relaxed afterwards — it's the confluence of sound and its effect on us, a greater awareness and breathing that influence the outcome.”
What health benefits do binaural beats have?
At a frequency of between 1 and 30 Hz, binaural beats may create the same waves commonly experienced during meditation practice. One study found that listening to binaural beats can reduce stress, while another meta-analysis found that they can affect cognition, anxiety levels, and the perception of pain, depending on the frequency. Other health benefits may include improved focus and concentration, a better mood, and heightened creativity.
Can binaural beats help you sleep?
According to “There’s no scientific evidence supporting the use of auditory stimulation to aid sleep,” says Peters. “That being said, the risks are minimal if someone finds it helpful, though the likelihood of [sound therapy] remedying a significant sleep issue is extremely low.”
Other sleep specialists believe that sound, which is used around the world as a form of healing, can make a difference. Their patients say that relaxing music can help quiet their minds and help them fall asleep. Assuaging stress and anxiety can, of course, improve sleep quality since that’s what keeps most people tossing and turning.
Are there any side effects?
Though there are currently no known side effects to binaural beats, “If you have a neurological condition, always consult your doctor before listening to binaural beats,” says Martinez.
“Volume is incredibly important,” he adds. “It should always be a comfortable listening experience and never too loud. When sounds are too loud, they can cause hearing loss, and there are other physiological effects that can impact blood pressure, heart rate, and stress levels. And keep in mind that everyone responds differently to sounds, sound frequencies, or any type of music for that matter. Sound and music choices are a matter of personal preference.”
How can I listen to binaural beats?
Examples of binaural beats are readily available online. Martinez has created many series, including a Sleep Series and a Binaural Beat series, that can be found on his website.
Spotify also features playlists, including this one with five-plus hours of sound in delta frequencies.
The effects of binaural beats may depend on how long you listen. They’ve been shown to be more effective with longer periods of listening, up to two hours, so it may be helpful to experiment with different lengths of time and see what works best for you.
