Biorhythms and sleep - stages of sleep

Stages of sleep

There are two main types of sleep: Non-REM (or NREM) and REM. NREM sleep consits of 3/4 stages of sleep, each deeper than the last. REM sleep (Rapid eye movement) is when you do the most active dreaming. Your eyes actually move back and forth during this stage, which is why it is called rapid eye movement sleep.

When you are awake, the pattern of brain waves given are typically Beta waves - low amplitude (height of wave) and high frequency (regularly occurring). When you are relaxed or meditating, Alpha waves begin to appear which are of high amplitude and lower frequency. 

EEGs- electroencephalograms measure gross brain wave activity.

EMGs- electromyograms measure the electrical activity of a muscle.

EOGS- electrooculagrams measure eye movement.

Non-REM sleep

Stage 1

Irregular and slower Theta waves appear. Breathing and heart rate is slowed down, body temperature drops and muscles relax. From relaxation to stage 1, dream-like, hallucinatory images can appear. This can feel as if we are falling. We can easily be woken up from this sleep.

Stage 2

K complexes appear, with a sudden increasein wave amplitude…