A cycle in biological or psychological activity that occurs lessthanonce every 24 hours.
Infradian rhythm
Menstrual cycle - occurs once, on average, every 28 days
Seasonal Affective Disorder (SAD) - a form of seasonal depression.
Examples of infradian rhythms
Many IRs are clearly controlled endogenously. For example the menstrual cycle is governed by the pituitary gland, releasing hormones to control ovulation.
However it is through that exogenous zeitgebers influence IRs. Menstrual cycle - influenced by pheromones, SAD influenced by light.
Russell et al (1980)
Took samples of sweat from women in one group and applied it to the top lip of women from another group.
The groups were kept separate, but the second groups menstrual cycle still became synchronised with the women from group 1.
Supports the idea that pheromones act as an EZ because the study was able to isolate pheromones as the sole factor that would cause the synchronisation.
AO3 of Infradian Rhythms
A strength of research into bodily rhythms is that it has many practical applications.
This suggests ongoing research into bodily rhythms can benefit real peoples lives.
