Friday, August 5, 2011

Surviving a heat wave, with or without power

by Dustin Merritt

According to the CDC, people suffer heat-related illness when the body's temperature control system is overloaded. The body normally cools itself by sweating. But under some conditions, sweating just isn't enough. In such cases, a person's body temperature rises rapidly. Very high body temperatures may damage the brain or other vital organs. Several factors affect the body's ability to cool itself during extremely hot weather. When the humidity is high, sweat will not evaporate as quickly, preventing the body from releasing heat quickly. Other conditions that can limit the ability to regulate temperature include old age, youth (age 0-4), obesity, fever, dehydration, heart disease, mental illness, poor circulation, sunburn, and prescription drug use and alcohol use.

In a vehicle if the vehicle is in proper working order, the A/C can be used to regulate temperature. Opening the windows as much as possible while moving if your A/C isn't working. If possible always park in shade.

Most of this is common sense, but one of the best advantages of having a vehicle is you can travel to a different climate many times within a half hour to an hour you could be in a nice shady canyon with nice tall trees and a breeze. In any car it is essential to carry lots of water. I would suggest a bug out bag in the trunk with water being the most important ingredient (at least 3 gallons of potable water in a black container that is changed out on an annual basis. Why black, it will keep light from reaching the water to keep growths down).

If your vehicle breaks down find shade outside of the vehicle. Do your work when the shadows are long. Try and revive the old Mexican skill of having a siesta in the middle of the day to wait for better weather in the afternoon or early morning. This is also the best time to drive. You save on gas and lessen the chance of over heating.

Now let's say that a drive up the canyon isn't an option for you and you are stuck at the house. In a humid environment you want to increase airflow to help the evaporation of sweat. An A/C system is nice to have, but a good fan is cheaper and also very effective. Let's say though that the power is out, then what? How did our forefathers survive back in their day?

They consumed plenty of water and sought shade. Sometimes it's better outside than in. Outside under a tree there usually is better flow of air.
In a dry climate you can moisten clothes and cloths to put over the skin.

But how much water do we need to intake? Well, the body can excrete through sweating, urination and other body functions up to 3 liters per hour, but can only intake into the circulatory system 1 liter per hour. This means that the most important thing we can do is not be in a deficit in our bodies water banks when the heat of the day comes. We should have water storage for at least three months of 1 gallon per person per day as a minimum.

To know how to survive any heat situation one must understand the real threats to ones self that the heat poses. Your main enemy is HEAT STROKE. But you also need to know the precursors to heat stroke. These are heat cramps, and heat exhaustion.

Symptoms of heat cramps are as the name implies:
Cramps in the stomach, possibly nausea and heavy sweating. This is your bodies first statement to you to lay low and find some good shade and breeze to cool off. If we ignore this precursor, then we proceed onto our next precursor of heat exhaustion.

Heat exhaustion has symptoms the same as heat cramps and also; profuse sweating, muscle weakness and cramps, dizziness and headache.

The body is now screaming at us to stop and rehydrate and seek shade and cool air. If we continue to ignore these symptoms the progress to heat stroke

HEAT STROKE is a very serious medical emergency and must be treated aggressively and hastily.

Treatment involves rapid mechanical cooling along with standard resuscitation measures.

The body temperature must be lowered immediately. The patient should be moved to a cool area (indoors, or at least in the shade) and clothing removed to promote heat loss (passive cooling). Active cooling methods may be used: The person is bathed in cool water or a hypothermia vest can be applied. However, wrapping the patient in wet towels or clothes can actually act as insulation and increase the body temperature. Cold compresses to the torso, head, neck, and groin will help cool the victim. A fan or dehumidifying air conditioning unit may be used to aid in evaporation of the water (evaporative method).

Immersing a patient into a bathtub of cool (but not cold) water (immersion method) is a recognized method of cooling. This method requires the effort of 4-5 people and the patient should be monitored carefully during the treatment process. Immersion should be avoided for an unconscious patient, but if there is no alternative, the patient's head must be held above water. Immersion in very cold water is counterproductive, as it causes vasoconstriction in the skin and thereby prevents heat from escaping the body core.

Hydration is of paramount importance in cooling the patient. This is achieved by drinking water (oral rehydration). Commercial isotonic drinks may be used as a substitute. Intravenous hydration (via a drip) is necessary if the patient is confused, unconscious, or unable to tolerate oral fluids.

Alcohol rubs will cause further dehydration and impairment of consciousness and should be avoided. The patient's condition should be reassessed and stabilized by trained medical personnel. The patient's heart rate and breathing should be monitored, and CPR may be necessary if the patient goes into cardiac arrest.

The patient should be placed into the recovery position to ensure that the airway remains open.

In environments that are not only hot but also humid, it is important to recognize that humidity reduces the degree to which the body can lose heat by evaporation. In such environments, it helps to wear light clothing such as cotton in light colors (middle eastern garb understands these principles the best), that is pervious to sweat but impervious to radiant heat from the sun. This minimizes the gaining of radiant heat, while allowing as much evaporation to occur as the environment will allow. Clothing such as plastic fabrics that are impermeable to sweat and thus do not facilitate heat loss through evaporation can actually contribute to heat stress.

In hot weather people need to drink plenty of liquids to replace fluids lost from sweating. Thirst is not a reliable sign that a person needs fluids. A better indicator is the color of urine. A dark yellow color may indicate dehydration. It is debated whether water or sports drinks are more effective to regain fluids; however, drinking only water without ingesting any salts will lead to a condition known as hyponatremia, or low sodium, which can cause sudden death from heart attack. By sweating and urination, humans lose salts, which need to be replaced along with fluids. (slight caution to not over consume water, as this can flush minerals and salts and can even cause death).

The Occupational Safety and Health Administration in the United States publishes a heat stress Quick Card [9] that contains a checklist designed to help prevent heat stress. This list includes:

Known signs/symptoms of heat-related illnesses
Block out direct sun or other heat sources
Use cooling fans/air-conditioning; rest regularly
Drink sufficient water
Wear lightweight, light colored, loose-fitting clothes
Avoid alcohol, caffeinated drinks, or heavy meals

Center for Disease Control
Tintinalli, Judith (2004). Emergency Medicine: A Comprehensive Study Guide (6th ed.). McGraw-Hill Professional. p. 1186. ISBN 0071388753.

Dustin Merritt
Emergency Seeds Inc
877 451 7333

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