What is the main cause of hypothermia?

The main cause of hypothermia is when body heat loss exceeds heat gain. Hypothermia occurs when the body is exposed to cold temperatures for an extended period, leading to a significant drop in core body temperature. Factors that contribute to this imbalance include environmental conditions such as cold air and water, wind chill, and wet clothing that accelerates heat loss.

While the body can generate heat through metabolic processes, particularly during physical activity, if the rate of heat loss surpasses the body's ability to produce and retain heat, hypothermia will develop. The body struggles to maintain its normal temperature, which can lead to impaired bodily functions and, in severe cases, can be life-threatening.

The other choices point toward unrelated factors: excess body heat gain does not relate to hypothermia, while high humidity levels and low physical activity can influence comfort levels and thermal regulation but are not primary causes of hypothermia in the presence of cold.