Hypothermia occurs when the body temperature is abnormally low; causing the body to lose heat faster that it can be produced. This can occur quickly or over time through exposure. For example, someone who is outside when the temperature is extremely low can be affected by hypothermia quickly. A person who is exposed to cool temperatures for a long period of time or are stranded in cool water can become affected by hypothermia slowly. Once the body temperature gets too low, vital organs including the brain become affected, making the person unable to think clearly.