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
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.
Brainwave entrainment
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.
Monaural Beats
There are three major combinations of sound waves that induce brainwaves effectively: monaural beats, binaural beats, and isochronic tones.
Binaural beats work by listening to different frequencies with both ears, so you would need to wear earphones to hear them. However, prolonged use of earphones while sleeping is bad for your ears. Isochronic tones are heterogeneous, making them unsuitable for inducing sleep. Therefore, Nightly chose to use combinations of monaural beats as they are soothing for the ears and do not require earphones.
Layered Monaural Beats
Nightly wanted to take a step further. To find the most effective monaural beats for inducing sleep, our team has performed several experiments and clinical trials, collaborating with the Institute of Applied Brain and Cognitive Science of Yonsei University. Through our studies, we found that layered monaural beats, a mix of several monaural beats, are far more powerful than normal monaural beats.
How can these layered monaural beats help you sleep better? Through a controlled experiment, we demonstrated that subjects' delta waves increased, on average, by 18% when they tuned in to layered monaural beats. Notably, one subject experienced an increase in delta waves by 28% in just 5 minutes. Our AI-powered algorithm that generates layered monaural beats is patented. You can access our layered monaural beats exclusively in the Nightly app.
Nightly is composed of a team of experienced engineers and medical doctors that work tirelessly to improve your sleep quality. We all have experienced sleep deprivation, so we understand its serious repercussions. Our team made a vow that we won’t stop until we help everyone make the most out of their sleep. We are here to make every minute of your sleep count, and we are excited to have you join us in embarking on a new sleep journey.