What is another limitation of circadian rhythms?
P - Studies into the sleep/wake cycle tend to use small samples, or one participant.
E - The people involved may not be representative of the wider population.
T - This therefore limits the extent to which these studies provide meaningful generalisations. Furthermore, Siffre observed that his own internal bodily rhythm slowed down by the time he reached 60, meaning age is a factor to be considered when drawing conclusion.