Biological Rhythms: Circadian Rhythms Flashcards
Define biological rhythms:
A change in the body processes or behaviour in response to cyclical changes within the environment
How are biological rhythms are regulated and governed:
- Endogenous pacemakers
- Exogenous zeitgebers
Define endogenous pacemakers:
The body’s internal body clocks that regulate biological rhythms
Define exogenous zeitgebers:
External factors in the environment which reset our biological clocks
Define circadian rhythm:
A type of biological rhythm that operates along a 24 hour cycle
What is an example of circadian rhythm?
- Sleep/wake cycle
- Core body temperature
Describe the Cave Study of Siffre (1962), (1972)
-First for two months where he slept and eat when his body told him to
Finding of Siffre (1962):
Had slightly above 24 hour circadian (25h)
Method of Aschoff and Rutger (1976):
Participants in a bunker for 4 weeks with no natural light.
Findings of Aschoff and Rutger (1976):
-Sleep/wake cycle of between 25 and 27 hours (apart from one which extended to 29 hours).
Conclusion of Aschoff and Rutger (1976):
-Endogenous pacemakers control the sleep/wake cycle in the absence of light cues.
Method of Folkard et al (1985):
Isolated 12 participants from natural light for 3 weeks (dark cave), manipulating the clocks so that only 22 hours passed a day
Conclusion of Folkard et al (1985):
- None of the Ps could adjust conformably to the pace of the clock
- Strength of the circadian rhythm
Practical application to shift work:
- Shown to lead to desynchronization of circadian rhythms
- Lead to cognitive and physiological effects
- Lack of concentration as 6am, more safety risks
- Shown to have a higher chance of heart disease
- Economical implications of worker productivity
What are the implications of shift workers having lapse in concentration?
To the economics:
- Hard to maintain worker productivity
- More accidents happening in the workplace
What is the application of research of circadian rhythms in terms of drugs?
Understanding and impact of wrong circadian rhythm can be treated with drug therapies
What are the issues with case studies?
Small sample - impossible to generalise to the whole population -May be other factors effecting circadian rhythms e.g age or gender
Why does a lack of methodology make it difficult to generalise?
Internal validity is lacking due to lack of control of confounding/ extraneous variables so unable to be clear of what caused the change in circadian rhythms
What was the lack of methodology?
Artificial lighting used
