Heat- and Cold-Related Emergencies

Hypothalamus location and functions

Hypothalamus (click to enlarge)

The hypothalamus is the center of various autonomic regulatory functions, including body temperature. When this area of the brain receives information about increasing or decreasing body temperature, it makes adjustments to keep body temperature within an acceptable range. This is important since the cells of the body cannot stay alive and healthy for long outside a normal temperature range.

Although the “accepted” normal body temperature is 98.6°F (37.0°C), normal body temperature varies from person to person, from body part to body part, and from hour to hour during the day. For example, an oral temperature reading between 97.7°F and 99.5°F (36.5°C and 37.5°C) may be considered normal. For more details, click body temperature.

How the Body Regulates Temperature

The sun

The sun

Thermoregulation is the ability of the body (through various functions) to keep its temperature within a certain range, even when the surrounding temperature is very different. If the body is unable to maintain its normal temperature, a heat- or cold-related emergency can result.

Heat is a byproduct of metabolism, the conversion of food into energy. Deep organs, especially the liver, the brain, and the heart, generate most body heat. In addition, the body also gains heat by shivering or any kind of physical activity. You help maintain body temperature by wearing appropriate clothing, minimizing exposure to harsh environments, staying hydrated, becoming acclimated over time, etc.

The skin assists in maintaining normal body temperature by reacting differently to hot and cold conditions so that the inner body temperature remains constant. Vasodilation and sweating are the primary modes by which humans attempt to lose excess body heat. Alternatively, vasoconstriction occurs in cold environments to reduce the amount of blood near the surface thereby retaining heat in the body’s core.

Heat-Related Emergencies

Several illnesses and other conditions can occur due to the overheating of the body. Here is a FAQ about exposure to extreme heat by the CDC. Heat-related illnesses can happen to anyone but the following contributing factors make a heat-related illness more likely: high humidity; strenuous activity; being young or old; having preexisting conditions like diabetes, heart disease, or obesity; and drug use.

To care for dehydration

Replace the lost fluid and electrolytes. If the patient is conscious and able to swallow, have the patient take sips of a sports drink, milk, juice, or water.

To care for more serious heat-related emergencies
  1. Move the patient out of the sun or away from the heat source and into a cool or  air-conditioned environment.
  2. Call for advanced medical personnel if you suspect heat stroke or must care for a life-threatening condition.
  3. Remove excess or sweat-soaked clothing. If the patient is experiencing muscle cramps, have the patient rest and gently massage or stretch tight muscles.
  4. If the patient’s body is hot, cool it quickly by immersing the patient in water up to the neck or by placing ice-water–soaked towels or cold packs all over the patient’s body. Keep cooling until more advanced medical personnel arrive or for at least 20 minutes.
  5. Continue to cool the patient’s body by applying cold packs around the head and neck, under the arms, and in the area of the groin.
  6. If the patient is conscious and able to swallow, have the patient take sips of a sports drink, milk, juice, or water.

Cold-Related Emergencies

Cold-related emergencies take the form of a general cooling of core body temperature to a dange4rous level (i.e., hypothermia) or the localized freezing of body tissue (i.e., frostbite). Factors that contribute to cold-related emergencies include air temperature, humidity and wind chill, water temperature, length of exposure, the patient’s age and medical condition, inappropriate clothing for the weather or activity, etc.

Degrees of frostbite

Degrees of frostbite (click to enlarge)

Like thermal burns, the depth of a frostbite can be expressed as first degree (frostnip), second degree (superficial frostbite), and third degree (deep frostbite).

To care for hypothermia
  1. Move the patient out of the cold environment, if possible, or make the environment warmer by lighting a fire and/or building a shelter. Remove wet clothing and dry the patient carefully. Be gentle at all times; avoid rough handling such as rubbing patient extremities or moving the patient briskly.
  2. Call for more advanced medical personnel and care for life-threatening conditions first. When checking for breathing and a pulse, extend the check for 30 to 45 seconds (an exception to the “no-more-than-10-seconds” rule).
  3. Rewarm the patient passively by wrapping all body surfaces with clothing or warm blankets.
  4. If you are far from advanced medical care, use active rearming techniques such as heat pads or hot-water bottles. Do not immerse the patient in warm water.
  5. If the patient is conscious and able to swallow, give warm liquids that do not contain alcohol or caffeine.
  6. Provide emergency oxygen, if available.
To care for frostbite
  1. Move the patient out of the cold environment, if possible, or make the environment warmer by lighting a fire and/or building a shelter.
  2. Handle the body part gently. Never rub the affected area, break blisters, or attempt to rewarm any body part if there is a chance it may refreeze.
  3. For minor frostbite (sometimes called frostnip or superficial frostbite), attempt to rewarm the part using skin-to-skin contact (without rubbing).
  4. For more serious frostbite, use warm water (about 105°F or 40.6°C) to rewarm the body part. Keep the body part in the water for about 20 minutes or until the part is warm to the touch.
  5. Loosely bandage the area with dry, sterile dressings. If fingers or toes are affected, place sterile gauze between them before bandaging.
  6. Take precautions to care for shock and prevent hypothermia.
  7. Do not allow the patient to walk on frostbitten feet or use frostbitten hands. Do not provide ibuprofen or other nonsteroidal anti-inflammatory drugs (NSAIDs).

Preventing Heat- and Cold-Related Emergencies

Emergencies caused by temperature extremes can be prevented by following these guidelines:

  • Avoid being outside or doing work during the parts of the day when temperatures are most extreme.
  • Wear clothing appropriate for the weather, the environment, and the activity.
  • Change activity levels often and take frequent rest breaks out of the extreme environment.
  • Stay hydrated in extreme environments. Drink cool liquids in the heat and warm liquids in the cold.
  • Wear an appropriate head covering in the heat and the cold. Protect your eyes from the sun. Protect fingers, toes, nose, and ears from the cold.