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

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.

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 complete—roughly 25 hours—the 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.

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.

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 (2:00 a.m. to 5:00 a.m.) Highest values commonly occurring in the evening (7:00 p.m. to 10:00 p.m.).

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.

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.

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.

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 0.1°F – 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

Alertness Rating Scale Chart Planned TimeActual TimeAlertness RatingBody TempNotes: 7:00 AM7:15 AM296.8°FJust woke up 9:00 AM 497.9TV AsleepDrowsyRelaxedAlertIntenseManic Psych I: Use page 26 in portfolio to put this chart on.