Biological Rhythms

• What is a cycle?


  A series of events that is continuously repeated in the same order
• What are biological rhythms?


  Processes in the body that follow a cycle
• What is a circadian rhythm?


  They are biological rhythms that repeat every 24 hours. Examples include the sleep-wake cycle and variations in body temperature.
• What is chronotherapeutics?


  Treatment timing (allows for a drug to be taken then delayed before being affective)
• Duffy conducted a controlled observation. She observed 2 categories morning people and evening people. Duffy found individual differences in the timing of people's circadian rhythms. Duffy found that individual differences in sleep/wake cycles are accompanied by individual differences in the timing of other circadian rhythms, like body temperature.
• What are ultradian rhythms?


  They are biological rhythms that repeat more than once every 24 hours. Examples of Ultradian rhythms are appetite and sleep stages.
• What are the stages of sleep?


  Stage 1 - We are just starting to fall asleep and can be easily woken up.

  Stage 2 - Our heart rate starts to slow down and our temperature starts to drop.

  Stage 3 + 4 - We fall into a deeper and deeper sleep.

  REM (rapid eye movement) - Our eyes move rapidly and our brain is active.
• How long does the stages of sleep cycle last?


  90 minutes
• What is the basic rest-activity cycle?


  The basic rest-activity cycle (BRAC) is an ultradian rhythm. One cycle of the basic rest-activity cycle (BRAC) lasts 90​ minutes.
• Tucker et al's research into individual differences in the sleep cycle


  Tucker et al. conducted a controlled observation into people’s stages of sleep. Tucker et al. found that there were individual differences in the amount of time people spent in each sleep stage. The study showed that ultradian rhythms can vary between different people.
• What are infradian rhythms?


  Biological rhythms that repeat less than once every 24​ hours. Examples being the menstruation cycle and hibernation.
• How frequently does the cycle for seasonal affective disorder repeat?

  Every year
• What is seasonal affective disorder (SAD)?


  It is when people experience low mood during winter and better mood during summer. It is an example of an infradian rhythm.