Heat-Related Emergencies

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As the U.S. enters Summer, we can expect hot temperatures to bake parts of the country. The state of Arizona is in the middle of a record-breaking heat wave that has seen temperatures of 115 degrees Fahrenheit. Even the cooler mountain areas are seeing highs above 100 degrees.

In other news, the country of India has experienced a killer heat wave that has taken, at last count, more than 2,300 lives. Although you often don’t hear these events called “natural disasters”, heat-related illness is responsible for more deaths yearly than hurricanes and tornadoes. A heat wave that blasted Europe in 2003 caused 71,000 fatalities.

In disaster settings, the loss of power can lead to major medical issues relating to heat. In an off-grid scenario, you may find yourself without shelter to protect you from the elements. If you haven’t prepared to deal with the weather, you have made the environment your enemy: You can be certain that it’s a formidable one.


Medical issues related to excessive heat are collectively known as “Hyperthermia”. These include:

Muscle cramps (Heat Cramps): Muscles spasm as a result of exertion in a hot environment. Calves, thighs, and shoulders are most often affected. Heat cramps may be caused by loss of elements called “electrolytes” in sweat, such as sodium, potassium, magnesium, and calcium . These are not replenished simply by drinking plain water. This issue was the main reason for the development of electrolyte-rich sports drinks like Gatorade.

Fainting (Heat Syncope): Blood vessels in the periphery of your body (for example, arms and legs) open up (dilate) in hot weather, causing less blood flow to the brain. The result is a short-lived loss of consciousness.

Heat Exhaustion: Often associated with dehydration in a hot environment, heat exhaustion is a group of symptoms due to an increased body core temperature. If untreated , it can lead to heat stroke.

Heat Stroke: Worsening symptoms caused by a body core temperature of over 105 degrees Fahrenheit. Life-threatening if not treated quickly.
The risk of heat-related illness correlates strongly to the “heat index”, a measurement of the effects of air temperature combined with high humidity. Above 60% relative humidity, loss of heat by perspiration is impaired, increasing the chances of heat-related illness. Exposure to full sun increases the reported heat index by as much as 10-15 degrees F.


Besides the heat index, a number of other factors make a person more prone to heat-related illness:

Age. The very young and the very old are most likely to be the first victims.
Health Status: Those with chronic illnesses like diabetes, heart issues, and lung disease are prime candidates for heat stroke. So are those who are carrying a significant amount of extra weight.
Exercise: Athletes and members of the military often find themselves exerting themselves in hot weather, and must guard against heat-related illnesses. The same goes for workers who wear heavy personal protection gear.
Lack of Acclimation: People that aren’t used to hot weather are especially sensitive to heat stroke. Heat waves cause a jump in heat-related emergencies.
Location: Urban environments have a “heat island” effect where asphalt and concrete store up heat, making days and nights hotter.
Medications: Certain medicines affect your ability to stay hydrated and your response to heat. Some blood pressure medications, diuretics, antihistamines, and even psychiatric drugs may predispose you to heat stroke. Alcohol and caffeine should also be avoided .
Climate Control: Modern air conditioning goes a long way towards decreasing the risk of heat stroke.


The ill effects due to overheating are called “heat exhaustion” if mild to moderate; if severe, these effects are referred to as “heat stroke”. This is a continuous process in which symptoms start piling one upon another. Heat exhaustion usually does not result in permanent damage, but heat stroke does; indeed, it can permanently disable or even kill its victim. It is a medical emergency that must be diagnosed and treated promptly to avoid long-term effects.

To make the diagnosis of heat exhaustion, a significant rise in the body’s core temperature is required. As many heat-related symptoms may mimic other conditions, a thermometer of some sort should be a component of your medical supplies.

In addition to muscle cramps, dizziness, and/or fainting, heat exhaustion is characterized by:

· profuse sweating,
· flushing
· rapid pulse
· weakness,
· confusion
· muscle cramps,
· headache,
· nausea and vomiting.
· fainting
· Temperature elevation up to 105 degrees F

The victim may exhibit some or all of the above signs and symptoms.

Cooling and rehydration are basic strategies to treat heat exhaustion. Move the patient to a cooler environment, such as inside a home or car with air conditioning or in a shady spot. Removes clothes to help with evaporation and spray with cool water if available. Small sips of water or a sports drink will be important to improve hydration status, even if the person is nauseous. Without fluids, the victim will only become more dehydrated.

Intravenous fluids may be necessary otherwise. Acetaminophen and ibuprofen may help decrease discomfort from muscle cramps.
If no action is taken to cool the patient, heat stroke may ensue. Heat stroke, in addition to the above-listed signs and symptoms of heat exhaustion, will manifest as loss of consciousness, seizures or even bleeding (seen in the urine or vomit). Breathing becomes rapid and shallow. The body core temperature may rise to 110 degrees Fahrenheit.

The skin is likely to be hot to the touch, but dry; sweating might be absent. The body uses sweating to cool itself down until it hits a temperature of about 106 degrees. At that point, thermoregulation breaks down and the body’s ability to sweat as a natural temperature regulator fails.
If not dealt with quickly, shock and organ malfunction may ensue, leading to permanent damage or even death.


When overheated patients are no longer able to cool themselves, it is up to their rescuers to do the job. If hyperthermia is suspected, the victim should immediately:

· Be removed from the heat source (for example, out of the sun).
· Have their clothing removed.
· Be drenched with cool water (or ice, if available)
· Have their legs elevated above the level of their heart (the shock position)
· Be fanned or otherwise ventilated to help with heat evaporation
· Have moist cold compresses placed in the neck, armpit and groin areas

Why the neck, armpit and groin? Major blood vessels pass close to the skin in these areas, and you will more efficiently cool the body core. In the wilderness, immersion in a cold stream may be all you have in terms of a cooling strategy. This is a worthwhile option as long as you are closely monitoring your patient.

Should you give oral fluids to a person who has experienced heat stroke. The answer is no if they have altered mental status. They could possibly have the fluids go down the wrong “pipe” and enter the lungs. This is called “aspiration” and could easily become life-threatening.


Heat-related illness is largely preventable with a little planning:

Clothing: Wear clothing appropriate for the weather. Loose, lightweight, light-colored clothing will allow ventilation and not absorb heat. Tightly swaddling an infant with blankets, simply because that is “what’s done” with a baby, is a recipe for disaster in hot weather. Have everyone wear a head covering. A bandanna soaked in water, for example, would be effective against the heat. Much of the sweating we do comes from our face and head, so towel off frequently to aid in heat evaporation.

Hydrate: If you can avoid dehydration, you will likely avoid heat exhaustion or heat stroke. Work or exercise in hot weather (especially by someone in poor physical condition) will easily cause a person to lose body water content. “Filling up” before doing work in hot weather will help stave off dehydration. Drink a pint of fluid (a sports drink with electrolytes is best) an hour during work sessions.

Work Sessions: Avoid scheduling these in the hotter parts of the day. Pay attention to heat advisories put out by your municipality and be sure to provide sunscreen (SP30 or greater) to your workers to prevent burns.

Carefully planning your outdoor work in the summer heat and keeping up with fluids will be a major step in keeping healthy and avoiding heat-related illness. Monitor the workload (and the workers) and you’ll stay out of trouble.

Joe Alton, MD

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