Biological Rhythms

biological rhythms = any change in a physiological activity that repeats periodically, the frequency determins what rhythm it is 

infradian = one cycle is longer than 24hrs

circadian = one cycle takes approximately a day 

ultradian = one cycle takes less than 24hrs

endogenous pacemakers = internal mechanisms that govern biologival rhythms - affected by enviroment 

exogenous zeitgeibers = influence biologcial rhythms, social cues

Infradian Rhythms:

example: female menstrual cycle: 10-14 days, oestrogen and progesteron levels are at their lowest, FSH levels rise, egg size triple, prepare for pregnancy 

Research support: Reinberg 

examined a women who spent three months in a cave with only a small lamp to provide light. Menstrual cycle to 25.7 days…