Use of isolated cold stress testing in determining normal lower extremity thermoregulation

Isolated cold stress testing was performed on 72 healthy subjects in order to evaluate the normal thermoregulatory potential of vessel beds in the acral areas of the lower extremity. Two patterns of response were demonstrated: a cool response in approximately 80% of subjects, and a warm pattern in approximately 20%. In the former, the responses to cold stress were more active and the temperatures lower; in the latter, there was little change in temperature in response to the cold stress. Both patterns correlated strongly with initial temperature, and neither pattern correlated with age, sex, or smoking habits. No subjects reported pain, numbness, or discomfort during the test. This study demonstrated that wide variations in thermoregulatory flow were possible without clinical symptoms, and suggested that nutritional blood flow was adequate to meet metabolic demands despite thermoregulatory modulation.