Which of the following symptoms indicates a person is suffering from hypothermia?

Hypothermia occurs when body temperature drops below the normal range due to prolonged exposure to cold conditions. The symptoms of hypothermia can include shivering, sluggishness, and confusion. Shivering is the body's initial response to cold as it attempts to generate heat through muscle activity. Sluggishness and confusion arise because the body's core temperature affects its ability to function properly, impacting brain function and cognition.

The other options listed are symptomatic of different conditions. Excessive sweating and headache could suggest heat-related illnesses, while nausea and vomiting are often associated with gastrointestinal issues. Fever and chills typically indicate an infection or illness rather than a state of hypothermia. In this context, the combination of shivering, sluggishness, and confusion specifically reflects the physiological responses that occur when the body is unable to maintain its normal temperature due to chilling effects.