circadian rhythms

• circadian rhythm

  the biological clock; regular bodily rhythms that occur on a 24-hour cycle

  
• light-dark cycle

  the most powerful phase-setting agent in circadian rhythms
• Melatonin

  A hormone manufactured by the pineal gland that produces sleepiness.
• Body temperature regulation

  -low early morning

  -high late afternoon or early evening

  -fluctuates 1 degrees in 24hours
• body temperature and performance

  -sprints run mostly in evenings so body temperature is higher

  -marathons mostly run in morning as body temperature is lower
• sleeping habits

  refers to a series of habits and rituals that can improve your ability to fall asleep and stay asleep, athletes compensate from having regular sleeping habits
• Cortisol

  stress hormone released by the adrenal gland
• Jet lag

  a disruption of circadian rhythms due to crossing time zones
• shift work

  P: strength - provides an understanding of adverse consequences of disruption

  E: shift workers experince reudced concentration around 6 in the morning meaning mistakes are likely to happen

  E: shift workers 3 times more likely to develop heart disease compared to routine workers

  L: therefore sleep/wake cycle has implications on the economy
• counterpoint

  P: limitation - use correlational methods

  E: hard to determine whether desynchronisation of sleep/wake cycle id cause of negative effects

  E: e.g. high divorce in shift workers may be due to strain in sleep deprived family members and missing out on important events

  L: therefore biological factors may not be the cause of adverse effects on shift workers
• medical treatment

  P: strength - used to improve medical treatments

  E: aspirin as a treatment for heart attack is most effective at night

  E: research found that heart attacks are most likely to occur early morning so the timing of taking aspirin matters

  L: therefore can help increase effectiveness of drug treatments
• individual differences

  P: limitation - generalisations difficult to make

  E: researcher found individual differences in sleep/wake cycle varying form 13 to 65 hours

  E: also some people naturally have a preference for being night owls or early birds

  L: therefore this makes it difficult to discuss any data other than averages