MILAN 



temperature during immersion is strikingly demonstrated by the 

 Indian and starvation groups. It is notable that rectal temperature 

 is higher in the starvation group than in the others, therefore, finger 

 temperature need not be related to the central thermal state. The 

 most important results relevant to the assessment of local cold 

 adaptation in vascular responses are shown in the comparisons 

 of habituated and control groups. BMR and rectal temperature 

 were the same for both. Yet the habituated group maintained a 

 significantly higher average finger temperature (P<0.05). Finger 

 temperatures of the groups just before immersion were in the 

 progression: Indian > habituated = control > starvation. The values 

 in C were, respectively, 35.2 ±0.16, 33.8 ±0.28, 33.7 ±0.40 and 

 29.5 ± 1.53. The mean finger temperature of the Indians was sig- 

 nificantly higher than that of the others (P < .05) but the differences 

 between the other means were not statistically significant. 



Gener al conclusions . It was shown that cold exposure of the 

 human hand can cause a local vascular cold adaptation, or a marked, 

 specific habituation to cold pain, according to the duration and inten- 

 sity of the local cooling. Further, it was shown that a general habit- 

 uation to the test procedure gives results which could be mistaken 

 for a local vascular cold adaptation. 



In conditions where man works outdoors in cold climates, it is 

 likely that he will endure prolonged periods of moderate hand cool- 

 ing and occasional periods of severe cooling. Hence, he might main- 

 tain higher finger temperatures through a vascular adaptation, and 

 suffer less pain, even when finger temperatures were very low, 

 through specific habituation. These adaptations, combined with a 

 general habituation to the environment, could result in marked im- 

 provements in manual efficiency as the cold season progressed. 



Yet another factor, which is incidental to these adaptations, may 

 favor the maintenance of higher peripheral temperatures in outdoor 

 workers. This is the higher basal metabolic rate which has been 

 measured in Eskimos and northern Indians. Whether the higher 

 BMR of these northern natives is mainly related to diet (Yoshimura 

 et al., 1952*) or to genetic differences has not yet been resolved 



conclusively. 



*Yoshimura, H., R. lida, and H. Koishi. 1952. Studies on the reactivity of 

 skin vessels to extreme cold. Part ni. Effects of diets on the reactivity of skin 

 vessels to cold. Jap. J. Physiol. 2:310-315. 



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