Circadian rhythms

circadian rhythm

a type of biological rhythm

examples of circadian rhythms

Sleep/wake cycle and core body temperature.

sleep wake cycle

daylight is an important EZ feel drowsy when it is night time and alert during the day demonstrates the effect of daylight on sleep wake cycle

cave study

Siffre is a self styled caveman who has spent extended periods underground to study the effects on his own biological rhythms deprived of exposure to sound and natural light access to adequate food and drink he resurfaced in mid september after 2 months in caves of Southern Alps believed it was mid august

decade later

findings

in each case

other research

Aschoff and Wever convinced a group of ppts to spend 4 weeks in a WWII bunker deprived of natural light all but one of the ppts (whose SW cycle extended to 29hrs) displayed a circadian rhythm bw 24 and 25hrs both Siffre's experience and the bunker study suggest that the natural SW cycle may be slightly longer than 24hrs but that it is entrained by EZs associated w our 24hr day

limitation

P-studies of SW cycles usually involve a small group of ppts

limitation

P-although ppts in A and W study were deprived of natural light

strength

P-practical app to drug treatments E-CRs coordinate a number of the bodys basic processes-heart rate and digestion E-this in turn has an effect of pharmacokinetics

strength

P-knowledge of CRs has given researchers a better understanding of the adverse consequences that can occur as a result of their disruption E-night workers engaged in shift work experience a period of reduced conc around 6 in the morning-meaning mistakes and accidents are more likely E-research also suggested a rel bw shift work and poor health-shift workers are three times more likely to develop heart disease this is due to the stress of adjusting to different sleep wake patterns L-research into SW cycle may have economic implications in terms of how best to manage worker productivity