FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

SWEATING NECESSARY TO PREVENT HEAT RELATED ILLNESS

Question: I've been putting new siding on our house. After I'd been working for several hours in the bright sun shine I became rather weak, nauseous, hot, and just felt lousy all over. I couldn't finish work that day and didn't work the next day, either. My wife thinks I had heat stroke, and I think I had the flu. I didn't see the doctor, so do you have any way to resolve this family discussion about my illness at this point?

Answer: I have no way to be certain about the cause of your illness, but I can make an educated guess and I think both of you have probably missed the correct diagnosis. Influenza is not particularly common in the summer months, and usually its symptoms are described differently than you did yours. I think your wife's concern over a heat related illness is more likely, but heat stroke is a life-threatening form of this problem. I suspect you had a less severe type of heat illness called heat exhaustion. Let me explain a bit more about these two problems.

Our organs operate efficiently in a very narrow range of temperatures, about 98 to 100 degrees Fahrenheit. The reason we can function well in a wide variety of environments from cold winter weather to the heat of summer is that the human body has effective methods for controlling the temperature of the organs in the head, chest and abdomen.

In a warm environment the body generates more heat from muscular activity than it needs to keep the organs at their optimal working temperature. The body deals with this situation by pumping more of the warmed blood to the skin where its heat can be released to the environment and by additional cooling from evaporation of perspiration. On a hot day you become "flushed" as the circulation in the blood vessels close to the surface of the skin is increased. You can also produce two quarts of sweat each hour! Wow, that's a lot of liquid.

Normally these and other temperature-control mechanisms, including air exchange in the lungs, do a satisfactory job. In some situations, however, these methods may not be sufficient to keep the body temperature down where it belongs. Prolonged exercise while in bright sunlight on a hot summer day such as you experienced is one of these situations.

If the internal temperature of the body increases above the optimal level, the body's organs start to work less efficiently, and this can produce telltale symptoms. A mild elevation, say to a temperature of 101 or 102, causes some general muscle weakness, nausea, headaches, dizziness, muscle cramps and clammy skin. This milder form of heat-related illness is called heat exhaustion, and I think this is what you had.

Heat exhaustion is treated by moving to a cooler place, preferably out of the direct sun light, and consumption of a large amount of fluids. This and a day of rest are usually the only treatments that are necessary.

In the most extreme cases of heat illness, the internal temperature may reach 105 to 107 degrees and cause serious damage to the liver, kidneys, brain and heart. This is called heat stroke, and it may be fatal without immediate medical intervention. Fortunately, you didn't have this. If you suspect someone has heat stroke, call emergency medical services immediately. Don't try to treat them yourself.

As in most situations, prevention of a heat-related illness is better than any treatment. To avoid getting into trouble again this summer, I'd suggest that you do two things: When you are working outside, you should take frequent breaks even if the job is almost done or it is inconvenient to rest and get out of the direct sunlight. You must also drink large amounts of liquid to replenish the water lost in perspiration. Remember that this can be up to two quarts each hour! These simple measures should let us each work and play in the summer heat without suffering heat related illness.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.