Summary and Recommendations - Immersion Hypothermia Chapter

Humans are homeotherms. The essential organs of homeotherms must be kept at a constant temperature. This means that heat production and heat loss must be in balance. When the body loses more heat than it produces, the temperature will drop below the set point of 37 °C. In mild hypothermia the core temperature is between 35 and 32 °C, in moderate hypothermia the core temperature is between 32 and 28 °C and in severe hypothermia the core temperature is below 28 °C