Thermoregulation and aging.

Worldwide climate changes, bringing long-lasting higher and lower extremes of temperature, are leading to an increased mortality rate in elderly people due to cardiocirculatory dysfunction. The ability of young adults to make physiological adjustments when exposed to low or high temperatures decreases with age. The purpose of this literature review is to assess the dysfunctions occurring in the elderly as a result of their reduced responsiveness to thermal stress. Physiological responses to cold environment induce a reversible plasma water shift from the intravascular to the interstitial and intracellular level due to peripheral vasoconstriction. This phenomenon occurs on exposure to cold water or air and even during facial cooling by a cold wind. Above-normal temperatures induce a reduction in intravascular water due to sweating. Older people are less able to cope with the increased viscosity of blood and are thus more liable to suffer a cardiocirculatory accident.