How does cabin temperature contribute to hypothermia risk in flight?

• A. High cabin temperature and humidity raise core temperature.
• B. Low cabin temperature and evaporative cooling lower core body temperature.
• C. Cabin humidity has no effect on body temperature.
• D. Elevated oxygen partial pressure prevents hypothermia.

Answer: (B)

When thinking about heat in the body, the balance between heat produced and heat lost to the surroundings is key. In a flight cabin, if the environment is cool, heat naturally flows from the warmer body into the cooler air. Evaporative cooling adds to that heat loss: sweat evaporates from the skin and moisture leaves with each breath, removing latent heat. In the dry, cool cabin typical of many flights, this evaporation happens readily, so heat loss is accelerated. If the body can’t compensate with metabolic heat production or insulation, the core temperature falls, increasing the risk of hypothermia. The other ideas don’t fit because a hotter cabin wouldn’t drive hypothermia, humidity’s role is secondary to the temperature gradient and evaporation rate, and oxygen levels don’t prevent cold-induced drops in core temperature.