✓ Exogenous Zeitgebers (AO1) Flashcards
What is Entrainment?
entrainment is the process of exogenous zeitgebers (external factors) in the environment resetting our biological clocks
the sleep/wake cycle is determined by an interaction of internal & external factors
Light as an EZ?
light is a key exogenous zeitgeber
it resets the body’s main EP - the SCN
light also has an indirect influence on processes in the body such as hormone secretion (melatonin) & blood circulation
Social cues & EZ?
new-born babies have free running cycles
by abt 16 weeks most babies are entrained onto the 24 hour sleep/wake cycle due to adults enforcing routine behaviour (e.g. mealtimes & bedtimes)
therefore to overcome jetlag, the best way would be to adapt to local times for eating & sleeping
What 3 researcher did studies that support Exogenous Zeitgebers?
Campbell & Murphy
Steel et al
Shih-Yu Lee
What was Campbell & Murphy’s study?
15 ppts were woken at various times during the night & a light was shone on the back of their knees
circadian rhythms were disrupted by up to 3 hours
suggests that light is a powerful EZ
don’t have to only apply to visual input but sun receptors too
What was Steel et al’s study?
monitored individuals in the arctic w constant daylight for 6 weeks
ppts kept sleep logs
5/6 ppts developed free running cycles longer than avg. 24 hours cycle
What was Shih-Yu Lee’s study?
mothers w premature babies in NICU can have more sleep disturbances
- due to both stress & the dim lighting
- desynchronises circadian rhythms
mothers were given bright light therapy over a 3-week period & sleep monitored
mothers reported improvement in sleep length/quality & less depressive symptoms
