[Acral rewarming. I: "Normal data" of a healthy adult population]

The acral rewarming test was investigated in 285 healthy subjects (mean age: 44.1; 20-71) to establish "normal" or reference values as a basis for interpreting patient data. The study was disposed in a manner to look also for possible diurnal and seasonal variations of the rewarming parameters. Healthy controls show a considerable interindividual variability in the speed and the pattern of acral rewarming, with a striking bimodal distribution of the individual values. This variability is mainly due to the factors "season" and "gender", while "age" and "daytime" are more related to basal finger temperature as to the rate of rewarming. According to these findings seasonal variations must necessarily be included in the definition of normal reference values of the rewarming test. In the healthy subjects neither personality characteristics (Freiburger personality inventory) nor the individual's psycho-social situation (Life Event questionnaire) and "depressivity" (Beck inventory) correlate with rewarming parameters. However, momentary "fatigue" (Visual Analogue Scale) correlates negatively and the sum of "somatic complaints" positively with acral rewarming time. The issue of variability in normative data is discussed with reference to clinical applications of the rewarming test in part II.