Relationship between body heat content and finger temperature during cold exposure

The purpose of the present experiment was to examine the relationship between rate of body heat storage ((S) over dot), change in body heat content (DeltaH(b)), extremity temperatures, and finger dexterity. (S) over dot, DeltaH(b), finger skin temperature (T-fing), toe skin temperature, finger dexterity, and rectal temperature were measured during active torso heating while the subjects sat in a chair and were exposed to -25 degreesC air. (S) over dot and DeltaH(b) were measured using partitional calorimetry, rather than thermometry, which was used in the majority of previous studies. Eight men were exposed to four conditions in which the clothing covering the body or the level of torso heating was modified. After 3 h, T-fing was 34.9 +/- 0.4, 31.2 +/- 1.2, 18.3 +/- 3.1, and 12.1 +/- 0.5 degrees C for the four conditions, whereas finger dexterity decreased by 0, 0, 26, and 39%, respectively. In contrast to some past studies, extremity comfort can be maintained, despite (S) over dot that is slightly negative. This study also found a direct linear relationship between DeltaH(b) and Tfing and toe skin temperature at a negative DeltaH(b). In addition, DeltaH(b) was a better indicator of the relative changes in extremity temperatures and finger dexterity over time than (S) over dot.