pros

• Siffre-cave study

  • lived in a cave for 2 months
  • natural circadian rhythm was ab 25 hours
• Siffre other cave study

  • he redid it for 6 months
  • For the first 35 days, Siffre had a sleep-wake cycle of 26 hours.
  • Sometimes it was 48 hours as the people in previous studies.
  • When his sleep-wake cycle varied, the cycle could be from 18–52 hours.
  • On day 150, he returned to a 26-hour cycle that lasted until the experiment's end.
• Siffres

  • done over long period of time
  • gathered qualitative and quantitative data
• stern and mcclintock

  • 20 ps
  • wiped sweat of other women on lips
  • 68% synced up
  • shows pheromones affect it- exogenous zeitgebers
• aschoff and weaver

  • put ppl in bunkers for 4 weeks
  • all but 1 had sw of about 24hrs
  • one had 29hrs
• Boivin (et al. 1996)

  Circadian rhythms - strength:Night workers engaged in shift work experience period of reduced concentration around 6am (circadian trough), increasing likelihood of mistakes and accidents.
• Knutsson (2003)

  Circadian rhythms - strength:Shift workers 3x more likely to develop heart disease.
• Baraldo (2008)

  Circadian rhythms - strength:Circadian rhythms have revealed certain peak times which drugs are most effective; as they coordinate main bodily processes, which has an affect on pharmokinetics. This has led to development of guidelines for timing of various drugs eg. anti-cancer, cardiovascular, respiratory, anti-ulcer, anti-epileptic.