Insidious hypothermia during raft use

Notes: It is commonly thought that increasing protection against cold water results in greater physiological efficiency in maintaining core temperatura.To examine the relatioship ofphysiological changes resulting from cold exposures as a function of increased insulation, five subjects (4 males, 1 female) wearing antiexposure ensembles covering the entire body and head were exposed in apool to water temperatures (Twater)=4.4o C and air temperature (Tair)=5.6o C. Trials consisted of subjects undergoing either head-out immersions with mean exposure time (t= 150+ 9 S.E.M. min) or enclosed within a raft (t=398+126 min.). Rectal temperatures were higher, and their relative change from baseline (Tre) smaller, for 3 of the 5 subjects at minute 122 in the water than in the raft. While no correlation was found between mean weighted skin temperature (Tsk), hand temperature (Thand), or foot temperature (Tfoot) with Tre, close correlation was found between Tre and forehead temperature (Tfore) (r=0.97,p<0.05) and change in forehead temperature (r=0.97,p<0.05). The results suggest that, during cold exposure, increased insulation, under specific conditions, may result in a lower Tre.ture (Thand), or foot temperature (Tfoot) with Tre, close correlation wa