Brain waves, which represent the electrical activity of the brain, fall within the very low-frequency range of the electromagnetic spectrum. These electrical oscillations are typically measured in Hertz (Hz) and are detected using electroencephalography (EEG).
Let’s look at the common types of brain waves and their typical frequency ranges:
Delta Waves (0.5 – 4 Hz):
- These are the slowest brain waves, associated with deep, dreamless sleep and regenerative healing.
Theta Waves (4 – 8 Hz):
- Associated with light sleep, REM sleep, deep meditation, and some states of creativity.
Alpha Waves (8 – 14 Hz):
- These waves are tied to states of relaxation while being awake, light meditation, and a bridge between conscious and unconscious mind.
Beta Waves (14 – 30 Hz):
- Represent the awake, alert state of mind. They’re associated with active, analytical thought and concentration.
Gamma Waves (30 – 100 Hz):
- These are the fastest brain waves and are associated with cognitive functions, information processing, learning, and perception.
Now, to put these brain wave frequencies into perspective within the broader electromagnetic spectrum:
- Radio Waves: These range from very low frequencies (like those used in AM radio, at hundreds of KHz) to higher frequencies (like FM radio, at tens to hundreds of MHz). Brain wave frequencies are much lower than even the lowest radio frequencies.
- Microwaves: Typically in the GHz range, like the 2.4 GHz or 5 GHz bands used in Wi-Fi.
- Infrared, Visible Light, Ultraviolet: These are even higher in frequency, ranging from hundreds of THz (teraHertz) for infrared to several PHz (petaHertz) for ultraviolet.
- X-Rays and Gamma Rays: These are at the highest frequency end of the electromagnetic spectrum.
Brain waves, given their very low frequencies, are at the extreme low end of the electromagnetic spectrum, far below radio waves. This is one reason why they don’t radiate efficiently from the head and need to be detected using sensitive electrodes placed directly on the scalp.