June 13, 2010 Heat and humidity make a dangerous combination The weather has been a bit wet this past week; and for runners, the combination of water and hot temperatures can be dangerous. It is sort of like a math formula, with rain + hot temperature = high humidity. Runners can run in the rain and - other than getting a little wet - not have much else to worry about. Hot temperatures can be handled with certain precautions by the runner, such as drinking plenty of fluids, running at a cooler time of the day and wearing clothes that wick the sweat away. It is when the two conditions combine that the situation changes. The body is designed to adjust to temperatures by sweating, and the evaporation of the moisture cools the body. That is why wearing a loose-weave fabric is good, as it absorbs more of the moisture and helps in cooling the body. A problem may occur when a runner runs without a shirt. The sweat can accumulate and not evaporate fast enough, and actually form a layer of water that prevents the body from cooling itself. When the humidity is high, this is when the air is so moist (like running in a sauna, as some runners say) that evaporation cannot take place, and that barrier of sweat sticks to the skin and the body starts to overheat. A runner may think that everything is going great because of the sweat on the body. If the sweat cannot evaporate, it is not cooling the body, but acting as insulation and heating that core temperature up. There are three problems with high temperatures, and most people think that they sort of start with the least serious and gradually build up to the very serious. The first symptom is heat cramps, where muscles tighten and you may have a slight muscle cramp. The next step is heat exhaustion, when the sweat stops but the body has sweat on it; the body feels cool (goose bumps on the arm); the hair on the back of your neck feels like it is standing up, and thinking becomes difficult. A good test is to try and do a simple math problem in your head; and if you find that answers are hard to come by, it means it is time to stop. I had the experience of early signs of heat exhaustion during a run one day; and I still do not know how I made it back to the house, as I had no idea where I was and had a hard time thinking about where to turn at the next block. The last, and most serious, symptom is heat stroke. Here the body stops sweating, the skin turns dry, the pulse rate becomes very rapid and it becomes almost impossible to keep running. The symptoms seem to follow this progression, but not necessarily in a slow recognizable sign. The first sign may be just be before heat stroke sets in, and it may occur very rapidly. That is the danger of running in the combination of hot temperatures and high humidity. Runners need to be very cautious and aware of how the body feels during these conditions. Drinking lots of fluids frequently before, during and after a run helps. Some runners like to take a wet bandanna and put it in the freezer an hour or so before the run, to put around their neck to keep cool. This feels great at the beginning of the run, but you will be amazed at how fast that bandanna warms up. It is not necessary to miss a run during the summer, but just be aware of how you feel. For some of you macho runners that think you can run through any of those symptoms, try not to be foolish, as even experienced runners have fallen victim to one or more of these problems. Listen to your body; follow safety precautions and stop running, find a cool place to rest and call it a day. If you find a runner in this condition, try to cool them down as much as you can by fanning them, pouring cool water on their skin, elevating the feet and calling for help from either police, the fire department or an ambulance service. Best to have prevention rather a serious problem. Dr. Maurice Johnson - better known around San Marcos as “Moe” - is a professor in the Department of Health, P.E., Recreation and Dance at Texas State University - San Marcos. Moe has been a fixture in the San Marcos running community - both as a runner and race organizer - since way back when Moby Dick was a minnow. His column on running and fitness appears each Sunday in the Sports section of the San Marcos Daily Record. • Recent “Running With Moe” Columns • Home • About the Club • Current News • Club Runs • Places To Run • TX Running Clubs • Running Links • Useful Stuff Upcoming Races • Race Results • Country Roads 10K & Kids Run • ARA-Moe’s Better Half Marathon • “Running With Moe” Contact Us!