The Effect of Caffeine on Body Temperature

Introduction The aim of this experiment was to determine the effect of caffeine on resting body temperature. This has to do with homeostasis, which is the maintenance of equilibrium. In other words, it is a stable body state. Homeostasis refers to the process of keeping the internal body environment in a steady state, when the external environment is changed (Homeostasis 2). Humans are warm-blooded creatures that generate body heat internally and maintain body temperatures at a fairly constant level – about 98.6oF (Chiras 3). In this experiment, the effect of different amounts of caffeine on resting body temperature was examined. Pure caffeine is a white powder, like what is found in caffeine pills, and is “a plant-based alkaloid which stimulates the central nervous system of any creature that ingests it” (Pollick). It is produced as a by-product of de-caffeinating coffee (Emsley 80). Caffeine is known chemically as 1, 3, 7-trimethyl-xanthine. It has xanthine as its core molecule, and attached to that are three methyl groups on atoms 1, 3, and 7. Caffeine is metabolised by the liver, which can take about 12 hours to remove 90% of any caffeine someone has consumed (80). Caffeine is a stimulant that increases the heart rate, blood flow, and respiratory rate, which in turn will increase body temperature. The thermoregulatory centre in the hypothalamus controls body temperature. It receives input from two sets of thermoreceptors: receptors in the hypothalamus itself monitor the temperature of the blood as it passes through the brain, and receptors in the skin monitor the external temperature (Homeostasis). Body temperature varies throughout the day as it fluctuates within a range. The standard body temperature of a human is 98.6oF, but can differ as to what activities one is doing, or the time of day, for example if the sun is shining. To measure body temperature in this experiment, an oral thermometer was used, as it is one of the most effective ways of

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