Circadian Rhythms

Siffre:

Two month study in a cave, his free-running biological rhythm was 25 hours, deprived of natural light

Folkard

12 people in a cave for 3 weeks, went to sleep at 11:45pm and woke up at 7:45am, researcher changed the clocks so a day was 22 hours. Only 1 pps could adjust to new regime, showing free running rhythm can't be overridden with external forces

Real-world application for shift work

Consequences of what can happen if people’s circadian rhythms are effected, most accidents in work place happen at 6am, therefore this can help people who work long hours and help their companies reduce hours so it is safe for them

Not Generalisable

Siffre was one man, he may have individual difference that the rest of the population doesn't have, therefore hard to apply his findings to rest of world, low population validity.

Real-world application for medical treatments

Aspirin (treatment for heart attacks) is most effective when taken at night as heart attacks are most-likely to occur in the mornings, so by the time it takes effect, platelet activity will have reduced.