Your Health

Guarding against hypothermia

Prolonged exposure to cold weather raises risk

Guarding against hypothermia

Winnipeg Health Region
Wave, January / February 2015

What is hypothermia?

Hypothermia is a dangerously low body temperature. Normal body temperature ranges between 36.2 C (97.2 F) and 37.5 C (99.5 F). If your body temperature is just a few degrees lower than this, your bodily functions slow down. If your temperature drops too low and stays low for more than a few hours, the body's organs can be damaged and there is a risk of death. With hypothermia, the whole body cools, not just one specific area, such as fingers or toes.

How does it occur?

Your temperature can drop gradually as your body is exposed to cold temperatures. This could happen if:

  • You spend a lot of time in a cold, unheated indoor environment.
  • You are outside in cold weather without proper protection against the cold, wind, rain, or snow.
  • You wear cold, wet clothing for too long.

Hypothermia is more likely to occur if something, such as an accident, keeps you from moving or being alert. Your temperature can drop very quickly if you fall into freezing cold water. Hypothermia can also occur after a heart attack or stroke.

Small children and older adults are more likely to have hypothermia. They may even get it indoors. The very young and very old use up energy reserves quickly, so it is harder for them to maintain a normal body temperature in cold surroundings. Also, the body's ability to maintain a normal temperature decreases with aging. Older adults may not be able to react as quickly when temperature changes occur. Chronic medical problems with the circulatory system, nervous system, or the thyroid gland also increase the risk of hypothermia.

You are also at greater risk if you are using drugs or alcohol.

What are the symptoms?

There are four stages of hypothermia: mild, moderate, severe and profound. Mild symptoms start with shivering, increased breathing rate and amnesia and progress to moderate and severe symptoms including stopping shivering, stupor, and a decrease in level of consciousness. Profound hypothermia would include loss of reflexes and voluntary muscle movement, and changes to heart rhythms. Usually hypothermia occurs gradually and progresses as follows:

  • Cold feet, hands, and face
  • Shivering (older adults may not have this symptom)
  • Fatigue
  • Drowsiness
  • Confusion, irrational thinking, amnesia
  • Hostile, irritable attitude
  • Cold skin on the chest and abdomen
  • Poor co-ordination and balance
  • Stiff, jerking movements
  • Slow, shallow breathing
  • Slowed or irregular heartbeat
  • Stiff muscles and some trembling
  • Loss of consciousness
  • Loss of heartbeat

How is it diagnosed?

The diagnosis is based on where you have been and your symptoms. The health-care provider will check for shivering, confusion, or other symptoms of hypothermia. Your body temperature is checked and will usually be less than 35.5 C (96.0 F).

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 to try to help while you wait for medical help:

If the person is not breathing or has no pulse, start rescue breathing (CPR). If the person is breathing:

  • Take off cold, wet clothing.
  • Wrap the person in blankets or other dry coverings (warm the blankets, if possible). If you must remain outdoors, cover the person's head (but not the face) and keep him or her from direct contact with the cold ground.
  • As soon as possible, move the person carefully to a warm place and begin rewarming. Rewarming must be done slowly to prevent a rush of blood to the surface of the body away from vital organs that need blood.

If rewarming cannot be done by trained medical personnel, do the following:

  • Remove any damp clothes and dress the person in dry clothes or cover the person lightly with blankets.
  • Give warm liquids to drink if the person is alert and not in danger of choking.
  • Allow the person to warm up gradually in a warm room.
  • Give the person a warm (not hot) bath.

When you are caring for someone who is hypothermic, do not:

  • Give the person hot liquids to drink.
  • Force the person to eat or drink anything.
  • Give alcoholic beverages.
  • Try to warm cold skin by rubbing or massaging.
  • Cover the person with heavy layers of blankets.
  • Allow the person to walk.
  • Use hot water bottles, heating pads, or electric blankets.

How long will the effects of hypothermia last?

How long the effects of hypothermia last depends on how badly the body organs were damaged. In many cases, you will recover in three to 12 hours with treatment. In severe cases, hypothermia can cause death.

How can I help prevent hypothermia?

The best way to prevent hypothermia is to be prepared and dress appropriately. Wear several layers of clothes rather than a single, thick layer. The best layers are those that provide good insulation and keep moisture away from the 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.

Hypothermia can occur when you least expect it. Follow these safety guidelines:

  • Be prepared for a sudden change in the weather. On outings, carry proper clothing in a backpack so you are prepared for bad weather.
  • Do not begin an outing too late in the day when weather could suddenly change.
  • Take off clothing when it gets wet and put on warm, dry clothes.
  • Drink plenty of non-alcoholic fluids. People who get hypothermia are often dehydrated.
  • Know the symptoms of hypothermia and the emergency treatment for it.
  • Keep space blankets (sheets of plastic and aluminum that help retain heat) and high-energy food handy in case of an emergency.

If you are over age 65, you should take the following precautions during cold weather:

  • 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 warm (above 18.3°C or 65°F).
  • Wear layers of warm clothing to help keep your body temperature even. Cover your head and neck, even indoors, if you have trouble keeping warm.
  • Stay dry.
  • Be sure to have and use enough warm blankets.
  • Practice good general health habits, such as getting plenty of rest, exercising, and eating nutritious food.
  • Keep a supply of nutritious food on hand that can be prepared easily. Eat hot meals and drink warm liquids throughout the day. Arrange for meals to be brought to your home if you are unable to cook.
  • Avoid alcoholic beverages.
  • Ask your health-care provider if any medicine you take might increase your risk of hypothermia. Drugs that reduce the body's ability to respond to cold include tranquilizers, cardiovascular drugs, sedatives, and antidepressants.
  • Take your temperature occasionally.

Audra Kolesar is a registered nurse and manager with Health Links - Info Santé, the Winnipeg Health Region's telephone health information service.

The information for this column is provided by Health Links - Info Santé. It is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a health-care professional. You can access health information from a registered nurse 24 hours a day, seven days a week by calling Health Links - Info Santé.

Call 204-788-8200 or toll-free 1-888-315-9257.

Wave: January / February 2015

About Wave

Wave is published six times a year by the Winnipeg Health Region in cooperation with the Winnipeg Free Press. It is available at newsstands, hospitals and clinics throughout Winnipeg, as well as McNally Robinson Books.

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