AO3

• Practical application to shift work - knowledge of rhythms has shown that shift workers experience adverse conditions such as the 'circadian trough'. This is a period of reduced concentration around 6 in the morning meaning mistakes are more likely to be made.
• Research has also shown that shift workers are three times more likely to develop heart disease du eot adjusting their sleep/wake cycle so this research has useful economic implications.
• Practical application to drug treatments - circadian rhythms coordinate a number of basic bodily responses (digestion etc) and research into this had revealed certain peak times during the day or night when drugs are more likely to be most effective. This led to the development of guidelines to do with the timing of drug dosing for a range of illnesses.
• Most research involves individuals (Siffre) or small samples and these people may not be representative of the wider population. This limits the extent to which these results can be generalised to everyone.
• Individual differences may effect the sleep/wake cycle - research shown some people prefer going to bed and getting up early (larks) whereas some prefer the opposite (night owls). This means it is too simplistic and ignores individual differences.
• Might be age differences in circadian rhythms - some psychologists believe teenager's rhythms begin two hours after adults.
• A pilot study in a North Tyneside school started the school day at 10am and found results went up, illnesses went down and the students were nicer to each other.