Circadian rhythm - A regular pattern with a 24 hour cycle, eg. Body Temperature.
Ultradian Rhythm - A cycle of less than 24 hours, eg. The Sleep cycle.
Infradian Rhythm - A cycle longer than 24 hours, eg. Menstrual cycle.
Endogenous Pacemaker - Internal Body clock.
Exogenous Zeitgeber - Environmental factor which acts as a time cue, eg. light
REM - Rapid eye movement, deep sleep.
NREM - Non-rapid eye…