Frostbite is when the extremities of the body - the ears, nose, or fingers - become too cold. Hypothermia is when the core temperature inside your body gets too low. Hypothermia can easily kill by slowing the function of vital organs like the heart, lungs and brain.
Frostbite, when properly treated, is not necessarily life-threatening.
The very young and the very old will succumb to cold much quicker. Small children are more susceptible to the effects of cold weather when they're dehydrated. They should get plenty of non-caffeinated fluids such as water, fruit juice and soup.
Wear lots of warm layers of clothing. Cover the head, ears, nose and hands. Wear warm footwear, Make sure the head is covered because a lot of heat is lost through the head. And remember that the wind makes the temperature even colder so children shouldn't be outdoors with exposed skin when the wind-chill is low.
As long as you maintain body temperature and are in good shape, you can exercise outdoors with no problem. If you have an underlying medical condition, like heart disease or asthma, you should be much more cautious. Some people experience what's known as exercise-induced asthma, where temperature changes in the airways cause them to become constricted. Cold and dry weather increases the likelihood of this condition.
Frostbite warning signs:
Frostbite is usually accompanied by a "pins and needles" feeling in the hands or the feet or the nose, followed by numbness or no feeling, and hardened pale skin. Blisters can form and sometimes it can lead to gangrene, which is accompanied by the blackening of skin that is seen in very severe cases.
Severe cases with blisters or worse need a doctor's attention. If you treat it yourself, re-warm the affected areas with warm - not hot - water. Immerse the extremity and circulate the water about every 30 minutes.
It's important to avoid refreezing the affected area. If you thaw out and it refreezes a short time later, it can make it worse. Do not use direct heat like a heating pad or a fire, because direct heat can easily burn a numb area. Also, do not rub or massage the area, because that can cause further skin damage.
Hypothermia can creep up very slowly. Violent shivering is one of the first signs, and may be followed by confusion, slow, shallow breathing, drowsiness, exhaustion and a weak pulse.
Hypothermia needs to be treated in a hospital. Get the person to an emergency room. While you're waiting for the ambulance, keep the person covered with a lot of extra clothing or warm blankets. Try to warm the torso first and then the extremities.