Circadian Rhythm

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Circadian Interference
Establishment of a ‘normal’ circadian rhythm in sleep/wake cycle and core body temperature and the effects of a sleep deprivation event on that rhythm.

Circadian rhythms are well documented and researched all over the natural world. Humans are subject to a circadian rhythm as well; being naturally diurnal animals, humans sleep during the night and are active during the day. It is also known that circadian rhythms affect more than just sleep wake cycles, but also many physiological processes and internal physical states such as core body temperature. The test subject for this experiment is a 22-year old male. The first question proposed for this experiment asks whether or not the subject has a circadian rhythm, and if he does, how consistent is it and what patterns does it follow?’ The primary hypothesis for this part of the experiment is that the subject does in fact have a circadian rhythm that is detectable in both his sleep/wake cycle and his core body temperature throughout the day; the null hypothesis is that no circadian rhythm is present and the subject exhibits arrhythmic behavior. To test the hypothesis the subject was monitored and his circadian rhythm over the course of fourteen days was analyzed. The monitoring process included keeping track of his sleep/wake cycle by noting times as accurately as possible when he woke up and when he fell asleep. The subject’s body temperature was also monitored at set times during his wake cycle throughout the day. The second part of this experiment was to study the affect of an interference event on the subject’s circadian rhythm. The interference event is to stay awake for a period of 24 hours or longer at one point during the observation period while continuing to monitor the subject’s core temperature at the preset time intervals. The first hypothesis for this part of the experiment is that interfering with the subject’s normal sleep wake cycle with offset his normal core temperature’s rhythm as well as his normal sleep/wake cycle, meaning that his temperature will be significantly more variable or significantly different after the interference event than before the interference event. The null hypothesis for this part of the experiment is that there will be no statistically significant change in my body temperature pattern after interfering with my normal sleep/wake cycle. A lack of significant change could be a result of the subject having a naturally variable enough rhythm that the interruption event was not traumatic enough to create any significant change in his rhythm.

Procedure and Methods:
The observation period over which the experiment was conducted was between the morning of January 30, 2008, and the evening of February 13, 2008. During this 14 day period, beginning the morning of January 30th the subject’s core body temperature was recorded using a digital oral thermometer at 8:00am, 12:00pm, 5:00pm, and 10:00pm every day. Proper recommended thermometer use was observed; no food or beverage was consumed within 15 minutes of making a temperature recording. The subject for this experiment was a 22 year old male, 6’4” tall and 235 pounds. All temperature recordings were done in degrees Fahrenheit. During the course of the experiment, on February 07, the subject’s circadian rhythm was interrupted by staying awake for longer than 24 hours; he woke up Morning of February 07 at 6:15a.m. and did not sleep until 8:30a.m. the morning of February 08. This cycle interruption was done in order to answer the second question posed by the experiment. Statistical analysis of the data collected was done using MINITAB statistical software as well as Microsoft Word.

Data and Results:
In the data collected in this experiment, all recordings of time are recorded as the hour being represented as a whole number while the decimal represents a fraction of an hour rather than the time in minutes. My recorded sleep times were done on a...
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