In July 1966, I was in my first year of residency at St. Louis City Hospital. A heat wave hit St. Louis that summer and there were two weeks with temperatures in excess of 110 degrees Fahrenheit everyday. Air conditioning was not as available then as it is now, and the temperatures in the apartments in the inner city were unbelievable. In the month of July, there were 530 deaths from heat stroke alone in St. Louis, Missouri. The common denominator for the individuals who died in this epidemic included being elderly, having heart failure to begin with, alcohol excess and prolonged exposure to excessive heat.

    In the mid-1980s, the main street of Pierre, SD, was widened and repaved with concrete. During the month of July, there was another heat wave in which temperatures exceeded 110 degrees Fahrenheit for about 10 days. On that occasion, there was one case of heat stroke and this occurred in one of the construction workers. What was the difference and what was the same about these two heat waves and the number of heat stroke cases that occurred? The first big difference is that Pierre, SD, is a relatively dry area whereas St. Louis, MI, has tremendous humidity. Perspiration works well to cool the body in a dry climate but it works very poorly in a very humid climate. The second difference is that air conditioning was much more available in the 1980s than it was in the 1960s and the elderly population with heart problems could be protected from the excessive heat. The one event which was the same in the two situations was alcohol intake. The gentleman who had heat stroke in Pierre in the mid-1980s was rehydrating himself with beer and that same method of hydration was noted in many of the heat stroke victims in St. Louis in the 1960s.

    Exactly what happens in heat stroke victims is not clear but the one pivotal event is that the sweat glands cease to work. The person will be relatively well maintained when for some reason unknown the sweat glands cease to make perspiration and then the body temperature rises dramatically with catastrophic illness. When this occurs, it is critical that the person be brought to a medical facility where effective cooling can be instituted, fluid support provided and medical treatment administered.

    Different than heat stroke in which the person does not perspire is a condition called heat exhaustion. With heat exhaustion, the person perspires more than the vascular system can support. Different than the person with heat stroke whose skin is hot and dry, the person with heat exhaustion will have skin that is moist and cold. Often times, the person with heat exhaustion may have a temperature that is actually normal or subnormal although a fever is the rule. With heat exhaustion, the person becomes delirious and often will collapse due to weakness. Fortunately, heat exhaustion does not carry the mortality that heat stroke does. With heat exhaustion, simple rehydration, rest and cooling are all that is needed.

    As an example, last summer I cared for an individual who was on his way to the Sturgis Rally with a truck and a large trailer of motorcycle equipment behind him. Unfortunately, his truck broke down and he needed to be towed to a service station. Disaster struck. During the towing process, the gentleman's truck and trailer came loose and wound up turned over in the roadside ditch. All of his motorcycles and motorcycle equipment in the trailer were in chaos. The gentleman became very distraught and then enraged at what he considered to be incompetence on the part of the tow truck operator. It was very, very hot that afternoon and as this gentleman was struggling to move motorcycle equipment out of his trailer, he became overheated and physically exhausted in his rage and collapsed. He was brought to the emergency room delirious with a very low blood pressure and sweating profusely. It was recognized that he was in heat exhaustion and intravenous fluids were provided. Soon, his blood pressure recovered and his ability to think recovered and he was able to leave the emergency room under his own recognizance after several hours. In addition to being an example of heat exhaustion, this gentleman is another example of Hoffsten's Rule #4, "You will never find a situation that your anger cannot make worse."

    The important rules to avoid heat exhaustion and heat stroke include being aware of the potential problem. Prolonged exposure to a hot environment day after day is a significant risk factor for heat stroke. Excessive exertion in a very hot environment can cause heat-related failure even in the acclimated individual. Appropriate precautions including intermittent rest, brief exposures to a cooler environment and adequate hydration are important. The use of alcoholic beverages for purposes of hydration has significant potential for causing problems.

    The elderly infirmed with heart failure are a special group that need care and help to avoid heat-related disease. Provision of adequate fluids and adequate cooling are critical. As the temperature rises, the strain on a person's heart is substantially increased. If a person's heart is already compromised, the risk of heart-related disease is much greater.

    The last heat-related disease to consider has a long medical name called a neuroleptic malignant syndrome. In a normal individual, the body temperature is controlled by muscle tension generated by the thermostat in the person's brain. When a person's temperature begins to drop, the brain involuntarily causes increased muscle tension or in extreme situations shivering. As the person's temperature rises and they tend to become too warm, muscle tension is released and relaxed again involuntarily by the brain. The practical example of this is the known relaxing effect of a heating pad when applied to a sore muscle.There are certain drugs that disconnect the wiring between the sensing center in the brain and the muscle tension center in the brain. When this happens, involuntary muscle tension becomes uncontrolled and large amounts of heat are produced. The person's muscles become very rigid, often very sore and their temperature can rise to 104 to 108 degrees Fahrenheit. This is an adverse drug reaction and can be reversed with appropriate medical intervention. Drugs that cause this neuroleptic malignant syndrome include Haldol, Thorazine, Compazine and others too numerous to name. Fortunately, simply stopping the drug and the use of a muscle relaxant medication can reduce the problem relatively simply.

    For all heat-related diseases, the best approach is avoidance. Protect the elderly and infirmed by keeping them cool with adequate hydration. For the working individual in a hot environment, arrange for periods of rest and cooling, provide adequate hydration and avoid alcoholic beverages as the primary hydrating fluid. Lastly, avoid the prolonged use of medications that can cause neuroleptic malignant syndrome unless those medications are absolutely necessary. Finally, be aware of the potential for heat-related illness in periods of prolonged heat when the temperature rises above 100 degrees Fahrenheit for several weeks in a row. This is the circumstance in which the body's cooling system fails and heat-related disease occurs.