Circadian Rhythms

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Circadian Rhythms
Only write notes for slides with this
symbol. Psych I Take notes on pg 25 of Portfolio
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What are Circadian Rhythms?

• Research conducted in caves, as well as in modern
  sleep laboratories where the environment is
  completely time-free, has proven that the human
  body is governed by built-in time setters,
  commonly referred to as an internal body clock.

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What are Circadian Rhythms?

• Over 100 body functions fluctuate between their
  minimum and maximum values once a day.
• These fluctuations in human functioning take
  about a day's time to completeroughly 25
  hoursthe term circadian rhythms was coined
  (circadian means "about a day" in Latin).
• Dr. Franz Halberg of Germany first used this term
  in 1959 to describe these changing body functions.

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Temperature

• One of the most easily measured of these
  circadian rhythms is the body temperature.
• Healthy humans experience rhythmic variations in
  their body temperature throughout the course of
  each day.

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Temperature

• For most people, the difference between high and
  low values is about two degrees Fahrenheit (97
  to 99)
• Lowest value typically occurring in the early
  morning hours (200 a.m. to 500 a.m.)
• Highest values commonly occurring in the evening
  (700 p.m. to 1000 p.m.).

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Temperature

• Studies in which the body temperature has been
  monitored in a time-free environment have shown
  that our temperature level fluctuates in the same
  25- to 26-hour pattern, no matter when we sleep
  or when we are awake. In short, our body
  temperature cycle operates independently of our
  sleep/wake cycle.

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Internal Desynchronization

• When the sleep/wake and body temperature cycles
  are no longer "in sync" with each other, we
  experience a condition known as internal
  desynchronization.
• An employee placed on the night shift must
  suddenly ignore the light-dark patterns in the
  external environment, and try to sleep at a time
  when the body temperature clock is telling him or
  her to be most alert and active.

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Circadian Rhythms Experiment

• For two days (this weekend) You will measure your
  temperature using a thermometer every 2 hours
  from the time you get up in the morning to the
  time you go to sleep.
• (If you can't measure your temperature every 2
  hours, then just measure it as often as it is
  feasible).
• Don't eat or drink anything 15 minutes before you
  take your temperature.

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Circadian Rhythms Experiment

• Make sure to take your temperature the same way
  every time and that you read the temperature VERY
  ACCURATELY....the differences in your body
  temperature are only a few 0.1 of a degree.
• Chart your body temperature
• Assess your state of alertness (asleep to hyper)
• Record body temperature to nearest 0.1F
• Notes Record what you were doing at the time
  (Reading, running)
• Only take temperature while sitting Do NOT do
  it while driving, walking, running or any other
  activity where you could bite the thermometer

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Alertness Rating Scale Chart
Asleep Drowsy Relaxed Alert Intense Manic
1 2 4 6 8 10
Planned Time Actual Time Alertness Rating Body Temp Notes
700 AM 715 AM 2 96.8F Just woke up
900 AM 900 AM 4 97.9 TV


Psych I Use page 26 in portfolio to put this
chart on.