Circadian Rhythms

• A strength of research into circadian rhythms is practical application to drug treatments.
• For example, circadian rhythms coordinate the body's basic processes (e.g. heart rate, hormone levels) with implications for pharmacokinetics.
• Research shows there are times during the day/night when drugs are more effective, which has led to guidelines being developed for the timing of dosing for a range of drugs including treatments for cancer and epilepsy.
• This strengthens both the applicability and support for research into circadian rhythms as it may have real-life medical benefits.
• A limitation of research into circadian rhythms is poor control in Siffre's cave study.
• For example, researchers questioned whether having access to artificial lights and cracks in the caves meant that Siffre hadn't eliminated all exogenous zeitgebers (light).
• This suggests that results he collated could've been influenced by extraneous variables, not truly measuring the influence that the SCN had on regulating a circadian rhythm.
• This weakens both the internal validity and support for research into circadian rhythms as Siffre may have ignored an important confounding variable.
• Another limitation of research into circadian rhythms is that individual differences may be an influence on results.
• For example, an issue complicating the generalisation of findings from studies of the sleep/wake cycle is that individual cycles can vary from 13 to 65 hours.
• Also, Duffy found some people display a natural preference for sleeping and rising early ('larks') but others prefer the opposite ('owls'), and that there are age differences in sleep/wake patterns.
• This weakens both the validity and support for research into circadian rhythms as findings may not fully represent individual differences within the population.