Delta waves and delta wave music is a fascinating topic. But it’s also complex. Luckily, the overall concept is easy to understand, only the science behind it can get confusing. After a lot of research, my goal is to help you understand how delta waves and music can help with sleep.
Summary: delta waves are a type of brain wave that we experience in deep sleep. They are a very low frequency wave. By listening to binaural music (music played simultaneously in your left and right ear at different frequencies), they create a low frequency wave that mimics your brain’s delta waves. The goal is to influence your brain into emitting delta waves, thereby promoting sleep.
This is part 2, which will explore the science behind brainwaves and sleep. If you missed part 1, which talks about the science of music, you can read it here.
Frequency: A Quick Refresher
I go into more detail about frequency in part 1, but let’s have a quick refresher:
Frequency is the number of occurrences of a repeating event per unit of time. We measure frequency (in terms of waves) in hertz (Hz). Hertz is measured as one occurrence of a repeating event per second.
So let’s give an example: you bounce a basketball once a second for 60 seconds. Its frequency is 60, since the repeating event (ball bounces) occurred 60 times in 60 seconds (unit of time). And its hertz is 1 Hz, since one ball bounce happened every second.
Now, let’s expand our knowledge of waves just a little bit more (this is not covered in part 1). Another property of waves is its amplitude. Amplitude is a measure of the distance between a wave’s maximum or minimum height and its resting point (the “middle” of the wave). Amplitude is best seen on a graph:
For our purposes, there is some extra information on this graph that we will ignore. The grey line going through the “middle” of the wave is the wave’s resting point, or point of no disturbance. In other words, before a wave has created a disturbance, such as a sound or vibration, the middle line is its resting state.
This can also be imagined by thinking of ocean waves. The flat, calm sea is the resting point before waves come to shore. As waves are created, the flat sea is disturbed.
So, as defined above, the distance between the wave’s resting point and its maximum or minimum point is the amplitude. This is only important because I will describe waves as having a high or low amplitude, so I wanted to make sure you knew what I was talking about.
What Are Brainwaves?
The human brain contains about 86 billion neurons. Neurons are electrically charged cells that communicate with other cells through a connection point known as a synapse. Synapses are the structure that permit a neuron to pass an electrical signal to another neuron.
Brainwaves are created when masses of neurons simultaneously communicate with each other through electrical pulses. There are several different types of brainwaves (discussed below), and they change depending on your activity level. As a quick example, slower brainwaves occur during relaxation and deep sleep, and faster brainwaves occur during heightened activity.
Brainwaves are measured and recorded using an electroencephalogram (EEG). Measuring brain activity with an EEG can be important in detecting, or determining, several different medical conditions, including sleep disorders, strokes, brain injuries, brain tumors, and, unfortunately, to determine if a patient in a persistent coma is brain dead.
Types of Brainwaves
There are five (5) main types of brainwaves, which I will discuss from highest to lowest frequency. As a quick note, the frequency ranges I give for each brainwave are estimates, and different studies will offer different ranges.
Gamma brainwaves are the fastest brainwave with a high frequency of 38-42 Hz and a low amplitude. Gamma brainwaves are a more recent discovery as they were originally ignored and thought to be “spare brain noise.” Research suggests that these brainwaves occur faster than our neurons can send electrical signals, so they are still somewhat of a mystery. It is thought that gamma brainwaves occur in highly active states, such as “higher virtues” or “expanded consciousness,” which may be related to some kind of spiritual awareness.
Beta brainwaveswaves occur during normal alertness or consciousness. These waves have a relatively high frequency of 12-38 Hz and a low amplitude. Whenever we are actively engaged in tasks, problem solving, making decisions, or any other active mental tasks, our brain is creating beta waves.
Alpha brainwaves occur during normal rest. These waves have a lower frequency of 8-12 Hz and a relatively high amplitude. Alpha brainwaves occur when you decide to rest after completing a task. This could happen while reflecting or meditating, taking a walk, or just sitting and not doing anything. In other words, alpha brainwaves occur in a state of non-arousal, whereas beta brainwaves occur in a state of arousal.
Theta brainwaves can be described as a “twilight” state. These waves have a low frequency of 3-8 Hz and a high amplitude. When you are daydreaming, your brain is creating theta waves. Theta waves also occur during repetitive, non-engaging tasks, such as driving on the highway for a long time or taking a shower. For the example of driving on the highway, if you’ve ever experienced driving for a long time and you suddenly can’t remember the last few minutes of driving, your brain was in a theta state. Theta brainwaves allow for the creative free-flow of ideas, and also occur while dreaming.
Delta brainwaves occur in deep, dreamless sleep. These waves have a very low frequency of 0.5-3 Hz and a very high amplitude. Someone in deep meditation could also experience delta brainwaves. Healing and restoration also occur in a delta state.
(Note: you may have noticed an inverse relationship between these waves’ frequencies and amplitudes. In other words, if frequency is high, amplitude is low, and vice versa. This inverse relationship is not a universal truth for all waves.)
Brainwaves, Sleep, and Music
As you noticed from the above descriptions, our brainwaves go through a natural progression during sleep. Brain activity expert Ned Herrmann explained the cycle of brainwaves we experience while falling asleep:
“When we go to bed and read for a few minutes before attempting sleep, we are likely to be in low beta. When we put the book down, turn off the lights and close our eyes, our brainwaves will descend from beta, to alpha, to theta and finally, when we fall asleep, to delta.”
This cycle, he further explains, will move in the opposite direction as we wake up. In other words, as we wake up, our brainwaves will ascend from delta, to theta, to alpha, to beta. This cycle will repeat about every 90 minutes during quality sleep, and it is the transition between delta to theta waves that we dream and achieve REM sleep.
So how do music and brainwaves relate?
I highly suggest you read part 1 to understand music’s role. But in summary: delta wave music occurs when listening to two different frequencies binaurally (one frequency in one ear, a slightly different frequency in the other ear). The two frequencies create a difference tone which we can’t hear, but our brain can. The goal is to create a difference tone that is in the frequency range of delta brainwaves. Hopefully, we will influence our brain to mimic those delta waves, thereby promoting sleep.
Like I said at the beginning, this is a complex topic to explain. Through parts 1 and 2, I hope to provide a general overview of this topic, how it works, and that I have made it easily understandable.
I will continue to research this topic, and plan on testing this theory by listening to delta wave music and see if it influences my sleep.
Let me know in the comments what you need further explanation on. I want to make this as understandable as possible, and will revise or update as needed (or even write a part 3).
Sources (click to be taken to source article):