THERMOREGULATORY RESPONSES TO COLD - EFFECTS OF HANDWEAR WITH MULTILAYERED CLOTHING

Background: Thermoregulatory responses were studied during rest and ex ercise in men wearing diverse handwear with an extended cold-weather c lothing system [ECWCS]. The ECWCS (thermal insulation = 3.6 do (1 clo = thermal resistance approximate to 0.155 m(2).K.W-1); weight = 10.1 k g) incorporates skin-tight polypropylene underwear, polyester/cotton f atigues, polyester-insulated liners, balaclava, vapor-barrier boots, a nd polytetrafluroethylene [PTFE]-lined outer garments. Methods: Six fi t males each rested (M = 71 W.m(-2)) and performed treadmill exercise (M = 171 W.m(-2)) while wearing the following handwear with the ECWCS: a light duty glove (LD, do = 0.86), a heavy duty glove (HD, do = 1.05 ), or an Arctic mitten (AM, do = 1.46). Cold exposures were at Ta = 0 degrees C, -20 degrees C, and -30 degrees C; rh = 20%; wind speed = 10 .34 m.s(-1). Exposure was a target period of 120 min designated as max imal endurance time (ET, min). All experiments were performed on separ ate days. Rectal (T-re), middle finger (T-mf), and mean weighted skin (T-sk) temperatures were recorded continuously; oxygen uptake and hear t rate were measured periodically and total body weight loss (m) over dot(sw), g.h(-1)) was determined after each run. Results During rest a t 0 degrees C, the ECWCS maintained T-re at 37 degrees C for the maxim al ET with all handwear configurations; for each lower ambient conditi on, steady-state Tre dropped -0.2 degrees C per each 10 degrees C decr ease in Ta. T-mf at or near 5 degrees C prior to the maximal FT was th e basis for premature attrition; T-sk of 29.4 degrees C was associated with subjective thermal discomfort. ET was predicted adequately by co mbining T-mf, heat production, T-re and T-sk. Conclusions: The ECWCS w ith specific handwear furnish adequate ET in cold-dry ambients provide d that ventilation and removal of extra layers is an option during hea vy exercise and thermal insulation is not decreased by body moisture.