AO3

• One strength of the research into circadian rhythms is that there is a wide application within drug treatments.

  For example, circadian rhythms have been shown to co-ordinate many basic bodily processes e.g. heart rate, digestion and hormone levels. This in turn affects the pharmacokinetics i.e. the actions of drugs in the body and how well they are absorbed and distributed.
• This is a strength because the research has revealed there are peak times during day and night where drugs are going to be most effective, which has led to the development of guidelines to do with the timing of drug dosing for a whole range of medications including anticancer, cardiovascular, respiratory, anti-ulcer and anti-epileptic drugs.

  As a result the applicability of the theories and research behind circadian rhythms is increased.
• What is one weakness of research into circadian rhythms?

  It has low internal validity
• Why is the access to artificial light in cave-type studies a concern?

  It may affect the biological rhythm
• What did Siffre do when he woke up in the cave studies?

  He turned on a lamp until bedtime
• What assumption did Siffre make about artificial light?

  It would have no effect on his rhythm
• What did further research do to participants' circadian rhythms?

  Adjusted them from 22 to 28 hours
• What was used to adjust participants' circadian rhythms in further research?

  Just dim lighting
• What does the original research not necessarily measure regarding sleep/wake cycles?

  The effect of daylight on sleep/wake cycles
• How does low internal validity affect the research into circadian rhythms?

  It impacts the credibility of the theories