What is the difference between passive and active external rewarming?

• A. Active rewarming uses external heat sources
• B. Passive rewarming uses the person's own heat with blankets or clothing
• C. Both involve external heat
• D. Passive rewarming uses external heat sources like warming blankets or warm water immersion

Answer: (D)

The main distinction is whether heat is supplied from outside or relied on the body’s own heat. Passive external rewarming means conserving and using the person’s own heat plus insulation—dry clothing, blankets, and a warm environment—so core temperature rises gradually without adding external heat. Active external rewarming, by contrast, involves applying heat from outside to the person, such as warming blankets, forced-air warming systems, radiant heaters, or warm water immersion, to raise the core temperature more quickly. In practice, passive rewarming is often used for milder cases or when slowing rewarming is preferred, while active rewarming is used when faster warming is needed or the person isn’t generating enough heat.