This Clinical trial is being conducted to study the effectiveness of heat donation through head or torso in hypothermic rewarming efficacy using a human model for severe hypothermia. The purpose of the study is to compare the core rewarming effectiveness of the same amount of heat donation through the head or torso in treatment of hypothermia using a human model for severe hypothermia. The information obtained from this study will give a better understanding of heat-transfer mechanisms. This might help in the ongoing research in hypothermia treatment.