Human thermoregulation; A synergy between physiology and mathematical modeling

This dissertation studies the regulation of the body temperature in both young and old people. Both the skin blood flow (regulation and heat release) and the energy use (heat production) were studied in a cool environment. In old people the core temperature went down, in contrast to the young people. There was, however, no difference in the change of the skin blood flow. On the other hand, young people increased the heat production, whereas that decreased in the elderly. Also, the blood pressure increased three times as much in the elderly as it did in the young people. The newly developed mathematical model shows that the decrease of heat production in the elderly is caused by cooling of the body. As opposed to young people, elderly people lose the capacity to compensate this decrease.