There are three things you should familiarize yourself with: sound itself, and how it works, the electromagnetic rhythms of your brain, and the vibrational energy of your cells.

Sound is vibration, or waves of air molecules oscillating as a result of the rapid, back-and-forth movement of an object. And if you'd like a crisp scientific definition:

“Sound waves are produced by a vibrating body, be it an oboe reed, guitar string, loudspeaker cone or jet engine. The vibrating sound source causes a disturbance to the surrounding air molecules, causing them to bounce off each other with a force proportional to the disturbance. The energy of their interaction creates ripples of more dense (higher pressure) to less dense (lower pressure) air molecules, with pressures above and below the normal atmospheric pressure. When the molecules are pushed closer together it is called compression; when they have pulled apart, it is called rarefaction. The back and forth oscillation of pressure produces a sound wave.”

A vibrating object, whether a guitar string or your own vocal chord, causes the air surrounding it to also vibrate. These sound waves hit your eardrums, making them vibrate, and that in turn causes waves in the fluid of your inner ear. Those waves are detected by various auditory nerves that relay the information to your brain to let you hear. Hearing, the detection of sound, isn’t detached from the physical world – it’s a physical effect, resulting from a physical cause. So it shouldn’t seem all that weird that certain frequencies of vibrating air impact your physiology and mental state.

Now onto brain waves. Neuroscientist Seth Horowitz wrote a book called The Universal Sense: How Hearing Shapes the Mind. He talks about the “right rhythms” for your brain, which may affect neurohormonal changes that occur over several months to a single neuron changing its activity state in milliseconds or less. With EEG (electroencephalography) machines, a few major rhythms have been identified that underpin the human cortex (the largest part of the brain that plays a key role in memory, attention, perception, cognition, awareness, thought, language, and consciousness), each of which changes under different physiological and cognitive conditions. The theta rhythm is the slowest (4-8 Hz) and rises at least in part from the hippocampus during memory processing. The alpha rhythm (6-12 Hz) is generated by connections between different parts of the cortex and the cortex and the thalamus. The beta rhythm (20 Hz) is generated in the motor cortex to control voluntary movement, and is usually only seen right after a person stops moving, acting as a sort of “off switch”. The gamma rhythm (40 Hz), may be involved in binding together individual sensory inputs and feedback loops that let you observe the world as a coherent, consistent environment.

But waves, rhythms and electrical vibrations don’t zap around just in your cranium.

These waves interact with your entire body and this is how sickness, disease, depression, and stress cause human beings to vibrate at a lower frequency, according to a JB Bardot article. There’s also a great book available titled Healing and Recovery, by Dr. David Hawkins. In it, he explains how frequencies, including audible frequencies produced by sound and music, can elicit either positive or negative emotion. And those frequencies can also elicit positive vibrations in different cells and tissues in your body – but they can also cause negative vibrations. That’s why some music makes you feel really good, while some can stress you out to no end.

Sound medicine is the science of biohacking these bodily rhythms that are vibrating in your brain, feet, and everywhere in between, in order to maximize the prominence and efficiency of specific wavelengths. Dr. Horowitz mentions a number of commonly-used strategies, like playing a tone or noise at a particular rate like the 8-10 Hz posterior alpha rhythm to induce relaxation. But methods like that are a bit simplistic, so he goes on to say that to get large portions of your brain hooked to a single rhythm, you need to expose yourself to a complicated input from a number of sources acting together. One way to do that is through binaural beating.

Most of the current research on binaural beats is based on the early 1970’s research done by biophysicist Gerald Oster, who showed that when a tone is played in one ear, and a slightly different tone is played in the other, the difference between the tones causes the brain to create a third, internal tone, which is the binaural beat. This syncs up the brain waves in both hemispheres, a process duly dubbed “brainwave entrainment”. In 2008, the journal Alternative Therapies in Health and Medicine published a review of twenty studies of brainwave entrainment and patient outcome and concluded that it is indeed an effective tool against cognitive functioning deficits, stress, pain, headaches, behavioral problems, and premenstrual syndrome.

Sound can even be used to treat more serious conditions than a simple lack of focus or drive, however. Ultrasound, whose most commonly-known use is observing the fetus in the womb, uses sound waves to produce a visible image. It’s also used to determine pain sources, as well as loci of swelling and infection. But lately, it’s taken on a more therapeutic application. Either by itself or in conjunction with drugs, it’s used to treat diabetes, stroke, cancer, cardiovascular diseases, infections, osteoporosis, thrombosis, glaucoma, nerve damage, skin wounds and bone fractures. And one of the primary ways by which it works is its interactions with cells and tissues. Hold on tight, things are about to get a little technical.

Your cells have what’s called electrical potential, by which they resonate and vibrate at specific frequencies that change under various circumstances. All molecules, including the ones that make up your cells, oscillate at a specific frequency, whose intensity is dependent on temperature. For single molecules and molecule groups, there are characteristic frequency patterns with defined peaks already used in modern chemical analysis. The characteristic spectra of molecular vibrations of many biomolecules have been determined for different tissue types, ranging from 1011 – 1014 Hz. Certain parts of tissue cells, like the cell membrane, endoplasmic reticulum, Golgi apparatus, and different microsomes representing polar lipids, will exhibit varying frequency patterns in different environments. When the cell is damaged, it reads the electromagnetic signals of specific frequencies in order to properly respond to the surrounding circumstances.

Now, ultrasound will actually elevate the temperature of the target tissue cells. It’ll also impact the vibrational frequency of the entire cell. And granted, different tissue types will react differently – osteocytes (bone cells) have a higher ultrasound absorption coefficient than muscle cells, so they react more dramatically. But ultrasound is still beneficial to the entire body. Perhaps the most dramatic effect is called “cellular cavitation”. Cavitation bubbles form when high-amplitude ultrasonic pressure waves travel through liquid. When the bubbles occur in close proximity, they rupture, and the resulting jets can rapidly stretch cells, poke holes in them or even obliterate their membranes, leading ultimately to cell death. Dying cells express a signal to the surrounding surviving cells to eat them and clean up the remains, a process known as “autophagy”. This is what makes ultrasound so effective against unhealthy, damaged, and/or tumorous cells. By targeting them, the ultrasound waves cause them to rupture and be swept up by the surrounding tissue cells.

To summarize:

Your body is literally humming (albeit very quietly) with energy at specific vibrational frequencies. When you’re healthy, you hum along at normal rates. But when something’s wrong with some part of your body, your cells, and therefore you, hum much more quietly and less efficiently. So in order to fully maximize your natural inclination to vibrate your way through breakfast, work, lunch, school, and dinner till you go to sleep and hum a different tune, you have to expose yourself to beneficial sound waves. There’s a wonderland of paraphernalia that can induce audio therapy, from sound healing ceremonies and crystal bowls, to music, to vibrating massage therapy tables and all sorts of other things out there that capitalize on your body’s response to vibration. So for the next little bit, enjoy a short and sweet introduction to sound therapy biohacks.