As stated by The Physics Classroom, “all objects have a natural frequency or set off frequencies at which they vibrate.” This extends to all matter, as everything in the universe is constantly vibrating, and each object’s unique properties determine its range of frequencies. This principle applies to people as well. For example, one study found that the standing human body’s resonant frequency (natural frequency) is between 9 and 16 Hz.

For reference, the Earth’s resonant frequency, also called the Schumann resonance, is about 8 Hz, and the frequency of the brain when relaxed, meditative, or daydreaming (Alpha waves) is around 8 to 13 Hz. Theta brainwaves, associated with deep meditation, internal awareness, and the time between sleep and wakefulness, are 4 to 8 Hz.

For thousands of years, people have used sound as both a form of art and a form of medicine. For example, ancient Greeks and Egyptians used music as a therapeutic for helping the sick, and Hindu and Buddhist faiths have used tones and chants such as “Om”, or “Aum”, to deepen their meditation and expand their spirituality.

Since long before the physics of sound was understood or the physiological effects discovered, music was used to energize and inspire warriors and soldiers in battle, lull children to sleep, and everything in between.

Music therapy is used in the modern world to help with a wide range of psychological and chronic ailments, though this field is still being investigated.

A significant factor contributing to music’s positive effect on the body is the release of dopamine that occurs while listening. When you hear a song that you enjoy, the chemical dopamine is released, bringing feelings of pleasure and satisfaction. Dopamine also helps regulate a number of important systems such as digestion, sleep and the circadian rhythm, memory consolidation, motor function, mood and emotional regulation, and more.