Strategies for prevention of cold stress in the elderly.

Human health and wellbeing require simple and effective strategies for prevention and alleviation of harmful effects of cold exposure. Adoption of a strategy should consider the type of cold stress; (1) whole body cooling, (2) extremity cooling, (3) convective cooling (wind chill), (4) conductive cooling (contact), and (5) airway cooling. The prime goal is to prevent tissue cooling. The risk, nature and magnitude of strain depend largely on the cooling effect, which results from the interaction of climate factors (mainly air temperature and wind), protection (clothing) and metabolic heat production (activity, "behaviour"). The effects (strain) of tissue cooling are acute, progressive or chronic. Acute effects are primarily thermoregulatory reflexes mediated by the sympathetic system and comprise immediate cardiovascular and respiratory reactions. Progressive effects are characterized by gradual temperature drop in peripheral or core tissues. This results in pain, neuro-muscular insufficiency, sensory loss and, eventually, cold injury. Chronic effects are likely to affect peripheral nerves and vessels, as well as cardio-respiratory function. The progressive degradation of physiological functions in the elderly increases the risk of harmful effects with cold exposure. This requires careful examination of relevant assessment criteria, as well as the development of simple and efficient strategies for prevention of cold stress.