Knowing the psychological effects of exposure to light, particularly blue light, has implications as technology changes and we are exposed to more blue light late at night from personal devices and new LED road lighting. This provides people advice on how to maintain a healthy sleep pattern
It seems that light is the main exogenous zeitgeber and social cues are less effective. Research on a man blind from birth by Miles (1977) showed hat even with social cues that blind man had a 24.9 hour circadian rhythm, meaning his sleep was out of synchronisation with the rest of society
One strength of research into circadian rhythms is that it provides an understanding of the negative consequences that occur when they are disrupted (desynchronisation)
What did research into shift work find?
Nigh workers engaged in shift work experience a period of reduced concentration around 6 in the morning meaning mistakes and accidents are more likely. Research also suggests a relationship between shift work and poor health. Shift workers 3 times more likely to develop heart disease compared to those who work more typical work patterns
Understanding of circadian rhythms has been used to improve medical treatments
Chronotherapeutics: how medical treatment can be admitted in a way that corresponds to a person’s biological rhythms. For example, aspirin as a treatment for heart attacks is most effective if taken last thing at night
One limitation into circadian rhythms is that generalisations are difficult to make
Small samplesizes used in studies (e.g. Siffre). Sleep wake cycle may vary widely person to person. Role of natural preferences and individualdifferences lead to cycles varying from 13 to 65 hours
