Circadian Rhythms AO3

• If circadian rhythms are disrupted, this can lead to problems
• People who do shift work might have difficulties, as working nights can lead to desynchronisation of endogenous pacemakers (internal body clocks) with exogenous zeitgebers (environmental cues)
• The effects include poor performance and bad judgement during night shifts, and increased risk of cancer, heart disease and depression
• Davis (2001): 'Breast cancer risk was increased among people who frequently did not sleep during the period of night when melatonin levels were at their highest (this lack of melatonin, normally released by the pineal gland, could increase the release of oestrogen by the ovaries)'
• Disruption to the normal sleep-wake cycle could have negative effects for people
• Individual differences


  Play a part in regulating circadian rhythms
• Duffy studied larks and owls, suggesting the sleep-wake cycle is not the same for all
• Siffre found differences in his own cycle when he repeated his research 10 years later
• Chronotherapeutics


  Studies how medicine could be most effective eg taking asprin to reduce heart attacks is best taken at night
• Circadian rhythms co-ordinate factors in the body
• Chronotherapeutics could be used to improve medical treatments