Adaptation

It appears that adaptation to cold temperatures can occur through repeated exposures. Radomski and Boutelier (1982) noted that men who had bathed in 15deg.C water for one-half hour over nine consecutive days before a trip to the Arctic showed less signs o f cold-induced stress than non-treated men.

There appears to be a cold-adaptive mechanism influencing mortality as well. In a study comparing winter mortality rates for 13 cities in different climates around the U.S., a large differential response was noted. The southern cities seemed to exhibit th e greatest increases in mortality during cold weather, while little or no response was found in northern cities (Kalkstein, 1984). In a city such as Minneapolis, no increase in mortality was noted at temperatures down to -40deg.C, but in Atlanta, mortalit y increases were evident if the maximum temperature did not exceed 0deg.C (Kalkstein ant Davis, 1985). Of the 13 cities studied, 7 demonstrated a statistically significant relationship between winter cold and mortality. The six non-significant cities incl uded cold weather locations (Minneapolis) and mild West Coast locations where very cold weather is virtually unknown (Los Angeles and San Francisco). "Threshold temperatures," which represent temperatures below which notable increases in mortality occur, were established for the seven cities (Kalkstein and Davis, 1985). The threshold temperatures were comparatively mild for the more southerly cities (0deg.C for Atlanta; 1deg.C for Dallas) and somewhat colder for the more northerly cities (-5deg.C for Phil adelphia). This differential geographical response seems to add credence to the importance of relative, rather than absolute weather conditions.