Dealing With Temperature Extremes

On the road to disaster, common sense is usually an early casualty. Somehow we talk ourselves into taking a hike on a shadeless trail when the temperature is 90 degrees and rising. On a wind-whipped winter's day, we convince ourselves to leave behind a potentially vital layer of clothing in order to save weight and bulk in our pack.

Nature is utterly indifferent to your presence in the backcountry. Human miscalculations during surges or drops in temperature may leave you vulnerable to weather-related injury or illness. The savvy wilderness traveler needs to know how to react when weather conditions move outside a human's customary comfort zone.

How to Handle the Heat

In warm conditions, your primary concern is to keep yourself hydrated. On a long hike in hot weather you may need to drink a gallon of water or more. That sounds like a lot, but it's not that hard to sweat away a quart of water every hour.

Without proper hydration (which typically requires fluid intake once every 20 minutes during strenuous exercise), your blood becomes thicker, like old motor oil. Your heart then must work even harder to force blood, which could become sludgelike, to circulate through your body. This could lead to a serious heat illness known as heat stroke.

Heat Illnesses

Heat illness is a general term that refers to a range of problems caused by the overheating of the human body.

• Heat Fatigue—This malady is usually characterized by muscle cramps, strong thirst and sudden, extreme fatigue.
• Heat Exhaustion—This occurs when heat fatigue worsens. Symptoms include excessive sweating, dizziness, headache, nausea and rapid heart rate.
• Heat Stroke—This is the most severe kind of heat-related illness. It's an extremely serious condition involving the total breakdown of the body's heat control system. Heat stroke victims usually suffer from severe confusion, a cessation of sweating and in some cases total nervous system failure. Heat stroke can be fatal.

Prevention

• Wear only lightweight, loose-fitting, light-colored clothing.
• Drink water often, and drink the coldest water available; your stomach assimilates it more easily.
• Start hiking before sunrise and during the fading light of early evening, when temperatures are cooler.
• Rest often. If you find a shady spot around midday, take an extended break.
• Start your trip in above-average condition; pre-trip training should have your body more accustomed to rigorous demands.

Remedies

• Stop all activity and rest in a cool, shady place.
• Drink water frequently.
• If the situation is serious, have the affected person lie down with their feet elevated to keep sufficient blood flowing to the brain.
• Place anything cold in places where major arteries are located: armpits, groin, neck. Add a wet bandanna on the forehead. Fan the person.
• Seek medical attention as quickly as possible.

Dehydration

Water is life. That's a slogan you'll see posted at ranger stations and visitor centers throughout the desert southwest in the United States. The words are true. If you become dehydrated, vital organs such as your kidneys, heart and brain are liable to malfunction. It is a serious condition that demands immediate attention. The aftermath could be shock, even death.

Dehydration is loss of water and important blood sugars and salts (electrolytes) such as sodium and potassium. Vomiting or diarrhea makes a person vulnerable to dehydration, but most backcountry explorers succumb to it due to overexertion. Its symptoms include:

• Increased heart rate
• Dark-yellow urine (or no need to urinate)
• Dry mouth
• Papery skin (pinched skin remains pinched instead of flattening)
• Weakness, lethargy
• Dizziness
• Muscle cramps
• Intense thirst
• Pain in the chest or abdomen
• Impatience
• Confusion

Your blood is roughly 90 percent water. As you exercise, your muscles heat up and perspiration occurs. Sweat evaporates on your skin's surface and cools it. This allows your bloodstream to circulate cooler temperatures to your internal organs.

If you do not regularly hydrate yourself, your blood thickens and it requires more exertion from your heart to pump it through the vessels. Thus you are doing your heart a favor by keeping your body well hydrated.

Prevention

• Drink water before you feel thirsty. Your body needs water before the sensation of thirst kicks in.
• Drink more at higher elevations. At oxygen-depleted heights, you breathe more rapidly and deeply to take in oxygen. This effort, combined with the intake of drier, colder air, increases fluid loss.
• Avoid alcohol and caffeine. They are diuretics and actually hasten dehydration.
• Some medications, including antihistamines and sedatives, can contribute to dehydration. Consult your physician for guidance.
• Do not substitute soda pop for water. Your body requires the unique attributes of water in order to function properly.
• Stay rested on your trip.
• Acclimatize gradually to high elevations.
• Eat well. About 25 percent of a human's daily water intake comes from food.

Remedies

• Drink almost any nonalcoholic liquid.
• Drink cold water; the stomach assimilates cold fluids with greater ease.
• Supplement water with fluids that contain electrolytes: juices, soups, performance drinks.
• If treating a seriously dehydrated person, encourage the person to accept liquids even though he or she seems disinterested. Persuade the person to accept at least a few sips every 10 or 15 minutes.

Coping With Severe Cold

Hypothermia

Hypothermia is a significant drop in the body's core temperature caused by prolonged or sudden exposure to the cold. This potentially life-threatening condition is surprisingly common among backcountry explorers, especially those who are not familiar with its early warning signs.

Subfreezing temperatures are not essential to cause hypothermia. Prolonged exposure to cold can lead to the condition. Sudden or acute hypothermia is usually caused by immersion in very cold water, which may afflict paddlers or winter travelers who break through ice. Wind can also play a role in the loss of body heat.

Hypothermia is dangerous because it develops subtly, often without the individual's knowledge. For this reason, wilderness travelers should occasionally check their companions for symptoms. Those include shivering, slurred speech or non-communication, apathy.

Prevention

• Stay warm, dry and well hydrated during your travels.
• Eat well, particularly at night. Digestion helps generate internal warmth.
• Begin your trip at a high level of physical conditioning. Your body will benefit from its heightened ability to circulate blood efficiently.
• If you have access to a fire or a heat source, position yourself so your body's "core" (the area between your lower chest and mid thighs) is closest to the heat. That is your body's furnace; it will help carry heat to your extremities.

Remedies

• Seek shelter.
• Warm your environment with heat from a fireplace, stove or furnace; inhaling warmed air benefits a victim.
• Remove wet clothing; replace it with warm items, including a head covering.
• Consume warm food and beverages.

Frostbite

Frostbite, the condition of skin freezing to a point where damage may be lasting, is a significant cold-weather hazard. When afflicted, the skin will have an ashen appearance and exhibit an odd discoloration and hard texture.

Remedies

• Seek shelter.
• Place the afflicted area in warm (not hot) water; sustain this activity for 30 minutes or more, even if this causes the victim some discomfort.
• Do not massage the afflicted area.
• Do not use a fire to thaw the damaged area.
• Do not allow treated areas to refreeze.

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