Human Cold Acclimatisation and Acclimation

he changes in an organism's responses to repeated or chronic exposure to cold environment are described as adaptation, acclimatisation, acclimation and habituation. In this paper the definitions described in the Glossary of Terms for Thermal Physiology (32) are used: Adaptation: A change which reduces the physiological strain produced by stressful components of the total environment. This change may occur within the lifetime of an organism (phenotypic) or be the result of genetic selection in a species or subspecies (genotypic). Acclimation: A physiological change, occurring within the lifetime of an organism, which reduces the strain caused by experimentally induced stressful changes in particular climatic factors. Acclimatization: A physiological change. occurring within the lifetime of an organism, which reduces the strain caused by stressful changes in the natural climate (e.g .. seasonal or geographical). Habituation: Reduction of responses to or perception of repeated stimulation. This paper focuses on the cold exposure of modern people. Usually, outdoor or indoor cold exposures cause peripheral cooling without significant whole body cooling, and the exposure time is limited. Consequently, the terms accllrnatisation, acclimotion and habituotion describe best the responses to that kind of cold exposure. Several recent reviews (3, 5, 16, 17, 20, 36) describe in detail different aspects of human acclimatisation and acclimation to cold.