Injuries Medical Encyclopedia Health Navigator Drug Interactions Drug Notes Health Capsules Smart Sites Back Pain Hip Pain Knee Pain Weight Loss Hypothermia Low body temperature; Cold exposure Definition Hypothermia is dangerously low body temperature, below 95 °F (35 °C). Considerations Other types of cold injuries that affect the limbs are called peripheral cold injuries. Of these, frostbite is the most common freezing injury. Non-freezing injuries that occur from exposure to cold wet conditions include trench foot and immersion foot conditions. Chilblains are a type of nonfreezing injury that develops in cold, dry conditions. You are more likely to develop hypothermia if you are:Very old or very youngChronically ill, especially persons who have heart or blood flow problemsMalnourishedOverly tiredTaking certain prescription medicinesUnder the influence of alcohol or drugs Causes Hypothermia occurs when more heat is lost than the body can make. In most cases, it occurs after long periods in the cold. Common causes include:Being outside without enough protective clothing in winterFalling into cold water of a lake, river, or other body of waterWearing wet clothing in windy or cold weatherHeavy exertion, not drinking enough fluids, or not eating enough in cold weather Symptoms As a person develops hypothermia, they slowly lose the ability to think and move. In fact, they may even be unaware that they need emergency treatment. Someone with hypothermia also is likely to have frostbite.The symptoms include:DrowsinessWeakness and loss of coordinationPale and cold skinConfusionUncontrollable shivering (although at extremely low body temperatures, shivering may stop)Slowed breathing or heart rateLethargy, cardiac arrest, shock, and coma can set in without prompt treatment. Hypothermia can be fatal. First Aid Take the following steps if you think someone has hypothermia:If the person has any symptoms of hypothermia are present, especially confusion or problems thinking, call 911 right away.If the person is unconscious, check airway, breathing, and circulation. If necessary, begin rescue breathing or CPR. If the victim is breathing fewer than 6 breaths per minute, begin rescue breathing.Take the person inside to room temperature and cover with warm blankets. If going indoors is not possible, get the person out of the wind and use a blanket to provide insulation from the cold ground. Cover the person's head and neck to help retain body heat.Once inside, remove any wet or tight clothes and replace them with dry clothing.Warm the person. If necessary, use your own body heat to aid the warming. Apply warm compresses to the neck, chest wall, and groin. If the person is alert and can easily swallow, give warm, sweetened, nonalcoholic fluids to aid the warming.Stay with the person until medical help arrives. Do Not Do NOT assume that someone found lying motionless in the cold is already dead.Do NOT use direct heat (such as hot water, a heating pad, or a heat lamp) to warm the person.Do NOT give the person alcohol! When to Contact a Medical Professional Call 911 anytime you suspect someone has hypothermia. Give first aid while awaiting emergency help. Prevention Before you spend time outside in the cold, do NOT drink alcohol or smoke. Drink plenty of fluids and get enough food and rest.Wear proper clothing in cold temperatures to protect your body. These include:Mittens (not gloves)Wind-proof, water-resistant, many-layered clothingTwo pairs of socks (avoid cotton)Scarf and hat that cover the ears (to avoid major heat loss through the top of your head) Avoid:Extremely cold temperature, especially with high windsWet clothesPoor circulation, which is more likely from age, tight clothing or boots, cramped positions, fatigue, certain medications, smoking, and alcohol Open References References Winkenwerder W, Sawka MN. Disorders due to heat and cold. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 109.Zafren K, Danzl DF. Frostbite. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, Pa: Mosby Elsevier; 2013:chap 139. Exercise - dress appropriately Illustration Exercise - dress appropriately Dressing appropriately is important when exercising in cold weather. Here are some tips to consider:Wear several layers, including gloves and a hat. Remove layers when you warm up, and replace them during the slower portions of your workout.If it is snowing or icy, be extra careful to not fall.Remember, you can still become dehydrated in cold weather, you still need plenty of fluid before, during, and after exercise. Skin layers Illustration Skin layers The skin is the largest organ of the body. The skin and its derivatives (hair, nails, sweat and oil glands) make up the integumentary system. One of the main functions of the skin is protection. It protects the body from external factors such as bacteria, chemicals, and temperature. The skin contains secretions that can kill bacteria and the pigment melanin provides a chemical pigment defense against ultraviolet light that can damage skin cells. Another important function of the skin is body temperature regulation. When the skin is exposed to a cold temperature, the blood vessels in the dermis constrict. This allows the blood which is warm, to bypass the skin. The skin then becomes the temperature of the cold it is exposed to. Body heat is conserved since the blood vessels are not diverting heat to the skin anymore. Among its many functions the skin is an incredible organ always protecting the body from external agents. Tests for Hypothermia Capillary nail refill test Capillary nail refill test A Closer Look Exercise Exercise Review Date: 01/13/2014 Reviewed By: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.