Final answer:
When your body temperature drops and muscles stiffen, it is a symptom of hypothermia, which occurs when the core body temperature falls below normal due to exposure to cold. The body reduces blood circulation to the extremities and muscles stiffen as a protective mechanism to conserve heat and maintain core temperature.
Step-by-step explanation:
When your body temperature drops and a symptom is your muscles stiffening, it is a sign of hypothermia. Hypothermia occurs when the core body temperature falls below normal, typically due to exposure to cold temperatures. In response to the drop in temperature, the body reduces blood circulation to the extremities and muscles stiffen as a protective mechanism to conserve heat and maintain core temperature.