VIDEO: Being outside in subzero temperature can be dangerous even if you're outside for just a few minutes. Your body can lose a significant amount of heat in a short amount of time, which can put you at risk for cold-related illnesses, such as frostbite and hypothermia. Firefighters use thermal imaging cameras in fire situations. They pick up a person's body heat, making it easier for firefighters to find someone trapped in a burning building. “We use it sometimes in the outside of the house to size up the scene when we get there. Then during the course of operations at a fire, it's used to help find victims, check for hot spots in the walls,” said Ryan Beckwith, a firefighter with the Madison Fire Department.