ABSTRACT
Survival in cold water depends on the extent to which thermal balance is maintained. Factors that affect heat loss in cold water include insulation provided by clothing and body fat, exposure time and water temperature. The magnitude of the thermogenic responses and the efficiency of insulative mechanisms against heat loss are decisive for whether man maintains heat balance or develops hypothermia during prolonged immersion. Studies in subjects wearing light clothing during cold water immersion have demonstrated that exercise accelerates the drop in rectal temperature compared with rest. The additional loss of body heat during exercise is explained by two factors. First, movement of the limbs through the water during exercise increases the convective heat loss. Second, exercise appears to increase circulation to the extremities where peripheral heat loss is optimized due to the short conductive pathway for heat transfer from the limb core to the skin surface.
