Effect of chronic local cold exposure on finger temperature responses.

17(2): 3’7-322. I g62.-Caucasian subjects from a temperate climate immersed their right index fingers in a stirred icewater bath for 20 min four times daily for I month. During subsequent test immersion, fingers exposed in this way showed an earlier initiation and a more rapid rate of spontaneous rewarming and a higher and more labile final temperature level than did either the same finger before the prolonged cold exposure or other digits not chronically cold exposed. The inference derived from these data that blood flow is elevated in chronically cold-exposed fingers was supported by digital calorimetric determinations. Since finger temperature responses were modified only in the cold-conditioned digit, the term “local cold conditioning” appears justified. Variation of the number of daily exposures made clear a progressive modification of skin temperature responses to cold. During the month of repeated cold exposures, pain associated with this type of cold exposure diminished and finally disappeared. These experimental data parallel most observations on peripheral vascular responses to natural cold exposures and may suggest a mechanism for the changes under both conditions.