What is hypothermia?

Hypothermia is a dangerously low body temperature. The average normal body temperature is around 98.6°F (37°C). If your body temperature drops just a few degrees lower than this, you will begin to shiver and blood vessels in your hands, feet, arms, and legs start to narrow. This helps your blood stay warm and helps keep your major organs supplied with blood. As your body temperature drops even more, your body functions slow down. You may not be able to shiver at this point. If your temperature drops too low and stays low for more than a few hours, your skin, blood vessels, and organs may suffer damage and there is a risk of death.

What is the cause?

Your temperature can drop if you are exposed to cold temperature for a long time. For example:

• You are outside in cold weather without a coat, hat, gloves, and shoes that protect against the cold, wind, rain, or snow.
• You wear cold, wet clothing for too long.
• You fall into cold water.

Hypothermia is more likely to happen if an injury, heart attack, or stroke happens in a cold place and keeps you from moving to someplace warm.

Babies, small children, and older adults are more likely to have hypothermia. Other factors that increase the risk of hypothermia are poor diet, dehydration, being overly tired, alcohol or drug use, low body weight, or chronic medical problems that affect your blood vessels or heart, nervous system, or thyroid gland. Medicines that affect your ability to stay warm include some heart medicines, sedatives, and antidepressants.

What are the symptoms?

Hypothermia usually comes on slowly. Symptoms may include:

• Cold skin
• Shivering (older adults may not have this symptom)
• Fast breathing and heartbeat at first, followed by a slow or irregular heartbeat and slow, shallow breathing
• Feeling tired or drowsy or trouble thinking clearly
• Problems with walking and balance
• Fainting or coma

How is it diagnosed?

The diagnosis is based on where you have been and your symptoms. Your healthcare provider will check for shivering, confusion, or other symptoms of hypothermia. Your body temperature is checked and will usually be less than 95°F (35°C).

How is it treated?

Hypothermia is a medical emergency and needs to be treated right away. Get emergency help right away or call 911.

If you are with someone who is hypothermic, here’s what you can do while you wait for medical help:

• If the person is not breathing or has no pulse, start CPR if you have CPR training.
• If the person is breathing, get them out of the cold if possible, remove their wet clothes and cover them with dry clothes or blankets
• Do not rub the skin, give liquids of any kind or use heating pads or electric blankets to warm them.

How can I help prevent hypothermia?

The best way to prevent hypothermia is to be prepared and dress properly. Wear several layers of clothes rather than a single, thick layer. The best layers provide good insulation and keep moisture away from your skin. Materials that do this include polypropylene, polyesters, and wool. Wear an outer garment that is waterproof but will also “breathe.” Wear a hat and keep your neck covered to help retain body heat.

When you are outdoors in cold weather follow these safety guidelines:

• Be prepared for a sudden change in the weather. Carry proper clothing and emergency supplies in a backpack so you are prepared for bad weather.
• Don’t begin an outdoor activity too late in the day.
• Take off any clothing that gets wet and put on warm, dry clothes.
• Drink plenty of nonalcoholic fluids. People who get hypothermia are often dehydrated.
• Keep space blankets (sheets of plastic and aluminum that help retain heat) and high-energy food handy in case of an emergency.
• Keep an emergency kit in your car with blankets, matches, food, and first aid supplies. If you get stranded in the snow, you can run the car for 10 minutes every hour to warm up. Make sure that the exhaust pipe is not covered and you have a window open slightly before you do this.

Hypothermia can also happen indoors, especially if you are over age 65 or have trouble keeping your home warm:

• If you are elderly and live alone, have someone check on you regularly during the winter. You should be checked at least once a day if it is very cold.
• Have your home properly insulated.
• Keep your living area above 65°F, or 18.3°C. Go to safe and warm places, such as shopping malls or community centers, during cold weather if you need to.
• Wear layers of warm clothing and cover your head and neck, even indoors, if you have trouble keeping warm. Be sure to have and use enough warm blankets.
• Stay dry.
• Practice good general health habits, such as getting plenty of rest, exercising, and eating healthy food. Eat hot meals and drink warm liquids throughout the day. Arrange for hot meals to be brought to your home if you are unable to cook.
• Don’t drink alcohol.
• Ask your healthcare provider if any medicine you take might increase your risk of hypothermia.
• If you cannot pay heating bills to keep your home warm, you can ask for help from agencies that can provide funds to help pay fuel bills, the Council on Aging, churches, or hospitals.