24-hr rhythm which is reset by the levels of light.
Sleep wake cycle?
light detected by the eye which sends messages to the suprachiasmatic nuclei (SCN). the SCN then dictates the sleep wake cycle
Body temp?
sleep occurs when core temp drops and then body temp rises towards the end of a sleep cycle promoting alertness
Siffre (1975)?
stayed in a cave with no clocks or light, he believed it to be one month earlier. suggest his 24 hr cycle was increased by lack of external cues making him believe that the days were longer.
Duffy et al (2001)?
morning people prefer to rise and go to bed early this demonstrates that there may be an innate individual differences in circadian rhythms.
Buhr et al (2010)?
fluctuations in body temp could be the determining factor. fluctuations in body temp caused tissues to become active or inactive
