Do you remember hearing anything before going to bed? Some of you may have fallen asleep to the vibrating noise of kitchen appliances or to the sound of a car passing in the distance. In today's world, where we are constantly surrounded by sound, it is difficult to fall asleep in a truly quiet, soundless environment.
In an effort to block out external noise, most of us probably have experience listening to sleep-inducing music or white noise, hoping it will help us fall asleep faster. But do these sounds actually help us fall asleep? Surprisingly, many sleep-inducing music and white noise on the web do not have scientific evidence that supports their effectiveness.
For the past two years, the Nightly team has been researching and developing AI-assisted sleep-inducing sound waves. And finally, we created “Layered Monaural Beats,” sound waves that have been scientifically proven to enhance sleep quality. Let’s dive into the science behind our technology and how it induces sleep effectively.
Brainwaves are electrical signals generated during nerve activity between neurons. Our brains produce five different types of brainwaves: gamma (30-100 Hz), beta (12-30 Hz), alpha (8-12 Hz), theta (4-8 Hz), and delta (0.5-4 Hz) waves. When we sleep, we usually produce low wavelengths ranging from delta to alpha waves. Here’s an interesting fact: we can train our brainwaves to a specific frequency by hearing sounds in a 'specific rhythm.’ This is called brainwave entrainment—the core science behind Nightly.
As mentioned above, brainwave entrainment refers to a phenomenon in which brainwaves are synchronized to a specific frequency. We focused on how synchronies occur when we sleep. Turns out, if you synchronize your brainwaves to a lower range of wavelengths, such as delta waves, your brain will generate electrical signals at a lower rate to induce deep sleep. This phenomenon has been tested and proven by many scientists for over 60 years.
Nightly found an example of this process of synchronization in a paper examining the relationship between brainwave entrainment and sleep. The study by Abeln et al. (2014) found that the sleep quality of subjects improved when brainwave entrainment was used. Other studies have revealed that brainwave entrainment can be used as a treatment for insomnia (Srinivasan et al. 2021) and facilitate sleep induction (Choi et al. 2019).
However, we cannot train our brainwaves by simply listening to sound waves of a specific frequency. To synchronize our brainwaves, we need to hear a combination of sound waves that correspond to the rhythm of that specific frequency. Thus, Nightly created combinations that use monaural beats to induce brainwaves at lower wavelengths.
There are three major combinations of sound waves that induce brainwaves effectively: monaural beats, binaural beats, and isochronic tones.