Beta waves (13 to 40 Hz ) - Beta is identified with active, busy or anxious thinking and active concentration.
Alpha waves (8 to 12 Hz ) - When we begin to relax or begin to get drowsy, but are still awake and conscious, when we are day dreaming, we are at the alpha level.
Theta waves (4 to 8 Hz) - When we are asleep and have dreams, and experience rapid eye movement (REM), and have hallucinations, and even when we experience deep meditation, we are at the theta level. When we lucid dream (this is when you are conscious while you are dreaming) we are at the theta level.
Delta waves (0.5 to 4 Hz) - Delta waves are usually associated with deep, slow brain activity found in deep sleep. Delta waves are experienced predominantly in newborn infants, as well as in healthy adults in deep rejuvenating sleep, or in very deep states of brain enhancing, emotional cleansing, bodily renewing meditation.