Infradian and ultradian rhythms - AO3

Question 1

What is a limitation of infradian rhythms?

Answer 1

• P: Limitation = confounding variables
• E: Synchronisation studies: stress, changes in diet and exercise. Explains inconsistent findings
• E: Trevathan et al. (1993): 29 cohabiting lesbian couples, no convergence in cycles
• L: So, pheromones are not an exogenous zeitgeber influencing the menstrual cycle

Question 2

What is a counterpoint for the limitation of infradian rhythms?

Answer 2

• P: Counterpoint = other zeitgebers
• E: Reinberg (1967) studied woman who spent three months in cave with only a small lamp for light
• E: Pp’s menstrual cycle shortened from the usual 28 days to 25.7
• L: So, other zeitgebers like natural light may influence infradian rhythms, even if pheromones do not

Question 3

What is a strength of infradian rhythms?

Answer 3

• P: Strength = application to treatments
• E: Phototherapy: simulates strong light, reduces symptoms in 80% (Sanassi, 2014)
• E: Preferred over antidepressants, no dangerous side effects or risk of tolerance/dependence
• L: So, benefits of determining the effects of exogenous zeitgebers on infradian rhythms

Question 4

What is a counterpoint for the strength of infradian rhythms?

Answer 4

• P: Counterpoint = effects don’t last
• E: Rohan et al. (2009): relapse rate of 46% over successive winters, vs 27% in group receiving CBT
• E: Issue with taking biologically reductionist approach to treatment
• L: So, research should consider influence of other factors (cognitive)

Question 5

What is a strength of ultradian rhythms?

Answer 5

• P: Strength = understanding and application
• E: Growth hormone is mostly produced during SWS; SWS is reduced in older people
• E: van Cauter et al. (2000): Sleep deficit may explain varies issues linked to old age, e.g. reduced alertness
• L: Relaxation and medication can be used to increase SWS, so practical value of research

Question 6

What is a limitation of ultradian rhythms?

Answer 6

• P: Limitation = individual differences
• E: Tucker et al. (2007): studied pps over 11 days and nights in a highly controlled laboratory environment
• E: Large differences, most significantly for deep sleep, due to genetics
• L: So, there is difficulty in research determining baseline for ‘normal’ sleep