Hypothermia is when the body gets very cold and can’t warm up on its own, according to UpToDate, a medical website. It occurs when the body, normally at 98.6 degrees, drops below 95 degrees.

The young and elderly are more susceptible. Symptoms include shivering (but they might stop shivering if it becomes extreme), clumsiness, trouble speaking clearly, confusion, tiredness, breathing faster than usual and urinating more than usual.