PHYSIOLOGICAL RESPONSES OF MEN IN SLEEPING BAGS AT ·20°C

~THODS Four male volunteers gave their informed consent to participate in these experiments. Each subject, wearing only shorts and instrumented with a rectal and 14 skin thennistors, lay on top of a Canadian Forces (CF) sleeping bag which was placed on a foam mattress on a rope mesh cot. A blanket was provided to keep him comfortable in the laboratory (20·C). After 60 min he got into the bag and donned the CF sleeping hood. The cot was then wheeled into the cold room (-20·C) where he remained for 120 min. Metabolic rate and body temperatures were measured continuously over the 180 min period. Experiments were performed using the CF sleeping bag, in either the single or double configuration. The insulation of the single bag was approximately 1.2m2KJW over the subject and O.2m2K./W under the subject and that of the double bag, was twice those values (1). The insulation of the foam pad was O.2m2K/W. Subjects were tested twice in each condition with the order of conditions randomly determined. Mean skin (Ts) and mean body (Tb) temperatures and changes in body heat content were calculated (2).