What is the condition of having a body temperature lower than normal?

Hypothermia is the condition characterized by a body temperature that falls below the normal range. Normal body temperature is typically around 98.6°F (37°C), and when the body temperature drops significantly, it can lead to serious health issues. Hypothermia often occurs due to prolonged exposure to cold temperatures, resulting in the body's inability to maintain its thermal balance. This can affect bodily functions and lead to severe complications if not treated promptly.

The other options refer to different temperature-related conditions. Hyperthermia, for instance, is the state of having a body temperature that is excessively high, often due to failed thermoregulation in a hot environment. A fever indicates an elevated body temperature usually due to an infection or illness, as the body responds to invaders. Chills are sensations of cold that can occur as the body attempts to regulate its temperature, often accompanying fever rather than indicating low body temperature. Therefore, hypothermia specifically points to the dangerously low body temperature condition.