Effects of Cold Temperature on Blood Pressure and Pulse

Christina Beat, Garrett Boyd, Matt Carara

            When mammals are subjected to cold temperatures, their bodies adapt in order to keep warm. They start shivering and the blood vessels constrict in order to maintain heat and create heat. If the body temperature continues to decrease, then organs can begin to shut down and hypothermia is possible. Blood pressure and pulse will increase in the colder temperatures because when the blood vessels constrict, it requires more pressure to get the blood throughout the body and the heart has to pump harder. Based on the above information, we hypothesized that in colder temperatures, the human body will work harder to keep warm, causing blood pressure and pulse to rise.

            To test this hypothesis we took blood pressure and the heart rate of three people in both room temperature and at a temperature below 40F. Subjects remained in the room for at least 20 minutes. After 20 minutes, the blood pressure as well as the heart rate of the subjects was taken. Subsequently the subjects went outside to the colder temperature: they remained in the cold for at least 20 minutes, to assure the body adjusted to the cold. After 20 minutes outside, the blood pressure and pulse rate of the subjects was taken. To assure no artificial heat, jackets were not put on before going outside, if they were not previously worn inside, as this would have changed body temperature.

            The mean results for room temperature of all three group members were: Blood Pressure = 111/77, Pulse = 72. The mean results for cold temperature (40F) of all three group members were: Blood Pressure = 135/97, Pulse = 75. These results show an increase in both blood pressure and pulse from subjects moved from a warm temperature to a cold temperature, although this may be negligible.

            Our hypothesis was supported by our results: blood pressure and pulse increase in the cold temperature. However, a t-test indicated that the difference was not significant which indicated our results were not statistically significant. The results might not be significant because the temperature change was not drastic enough to greatly affect the body. The experiment could be improved if more trials were conducted and if even colder temperatures were introduced. With more trials, we could decrease the amount of experimental error. Other studies showed a direct correlation between temperature and blood pressure/pulse. In a study conducted by Rosenthal (2007), twenty-two people had an increase in blood pressure when subjected to the winter season compared to the summer. Additionally, in a 2006 study done at the University of Kuopio by Matt Mattila, the twenty volunteers experienced a sharp pulse drop when going from room temperature to negative five degrees Celsius.







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