HAND AND FINGER SKIN TEMPERATURES IN CONVECTIVE AND CONTACT COLD-EXPOSURE

The present study aimed at investigating the spatial variability of sk in temperature (T-sk) measured at various points on the band during co nvective and cold contact exposure. A group of 8 subjects participated in a study of convective cooling of the hand (60 min) and 20 subjects to contact cooling of the finger pad (5 min). Experiments were carrie d out in a small climatic chamber into which the hand was inserted. Fo r convective cold exposure, T-sk was measured at seven points on the p almar surface of the fingers of the left hand, one on the palmar surfa ce and one on the dorsal surface of the hand. The air temperature insi de the mini-chamber was 0, 4, 10 and 16 degrees C. With the contact co ld exposure, the subjects touched at constant pressures an aluminium c ube cooled to temperatures of -7, 0 and 7 degrees C in the same mini-c hamber. Contact T-sk was measured on the finger pad of the index finge r of the left hand. The T-sk of the proximal phalanx of the index fing er (on both palm and back sides), and of the middle phalanx of the lit tle finner was also measured. The variation of T-sk between the proxim al and the distal phalanx of the index finger was between 1.5 to 10 de grees C during the convective cold exposure to an air temperature of 0 degrees C. Considerable gradients persisted between the hand and fing ers (from 2 to 17 degrees C at 0 degrees C air temperature) and betwee n the phalanges of the finger (from 0.5 to 11.4 degrees C at 0 degrees C air temperature). The onset of cold induced vasodilatation (CIVD) o n different fingers varied from about 5 to 15 min and it did not alway s appear in every finger. For contact cold exposure, when T-sk on the contact skin cooled down to nearly 0 degrees C, the temperature at the area close to the contact skin could still be 30 degrees C. Some case s of CIVD were observed in the contact skin area, but not on other mea suring points of the same finger. These results indicated that local t hermal stimuli were the main determinents of CIVD. Representative hand skin temperature may require five or more measuring points. Our resul ts strongly emphasised a need to consider the large spatial and indivi dual variations in the prediction and modelling of extremity cooling.