Biological rhythms

• How long are Circadian Rhythms? 


  Circadian rhythms last 24 hours
• Give an example of Circadian Rhythms 


  The sleep-wake cycle
• What is a strength of the research into Circadian rhythms?


  It can be used to improve medical treatments as Circadian rhythms coordinate lots inside the body, this can be seen through taking aspirin to reduce heart attacks is best late at night.
• What is a negative of the research into Circadian rhythms? 


  Individual differences may play a part in regulating Circadian rhythms- Duffy found that 'morning people' prefer to rise and go to bed early (about 6 am and 10 pm) whereas 'evening people' prefer to wake and go to bed later (about 10 am and 1 am), suggesting the sleep-wake cycle is not the same for all.
• How long are Ultradian rhythms? 


  Ultradian rhythms are cycles that last less than 24 hours
• What is an example of Ultradian rhythms?


  An example of Ultradian rhythms is the pattern of human sleep.
• Give a strength of the research into Ultradian rhythms


  It gives us an improved understanding of how the sleep cycle changes with age. Growth hormone is produced during sleep, so older people sleep less
• Give a weakness of research into Ultradian rhythms


  Conclusions drawn from this research may lack validity. For example, the sleep cycle is hard to investigate in a lab as pps are attached to monitors and any sleep that takes place may not be reflective of sleep without any distracting monitors. Therefore, it may lack ecological validity
• How long are Infradian rhythms?


  Infradian rhythms are cycles that last over 24 hours
• What is an example of Infradian rhythms? 


  An example of Infradian rhythms is the menstrual cycle or S.A.D
• What is a strength of the research into Infradian rhythms?


  Terman found that SAD is more common in Northern countries. As nights are longer, more melatonin would be produced. 10% of Northern US residents had SAD, compared to only 2% of Southern, suggesting light/melatonin does play a part. Furthermore, lightboxes can be used to treat SAD- Sanassi found it helped 80% of people with SAD to improve, which is a real world application
• What is a weakness of research into Infradian rhythms?


  It can be difficult to study things like the menstrual cycle as stress, exercise and other factors can change the cycle.