San Marcos Mercury | Local News from San Marcos and Hays County, Texas
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July 31st, 2009
Running in heat

Run with Moe: A column
San Marcos Runners Club

It seems like it is a little late to mention that when the hot weather arrives, runners need to be cautious of heat related problems.

We have had hot weather now for some time, and runners too often find out from experience that you have to adjust your running distance and speed for the daily run. Usually this means a shorter distance and a slower time.

The most common problems associated with hot weather running are heat cramps, heat exhaustion and heat stroke.

Heat cramps for a runner are often hard to recognize because the muscles get tired and uncomfortable on long runs. This is a common malady, and the runner may associate the discomfort as muscle fatigue and not heat cramps.

Heat exhaustion is another matter. The body will sweat, and that is also expected while running on a hot day.  The difference is that it is a “cold” sweat and the runner may experience “goose bumps” on the arms. There may be a prickly feeling on the back of the neck, and concentration seems to be difficult. Simple math problems, pace calculation, and even where the runner is on the route become hard to figure. These are some of the signs of heat exhaustion. When any of these warning signs appear, it is a signal that the run is over and the runner needs to find a cool place to rest and get some cold water into the body. Do not try to push through these warning signs, as the next step is possible heat stroke.

Heat stroke is very serious. The skin becomes dry, the pulse rate becomes very rapid and the skin feels hot. Shortly after these signs appear, the runner will find that he can’t run, so he will start to walk and may even stagger and fall down. Cooling the body is critical now, and cold water over the entire body is a good start if the runner is still able to function. A good garden hose shower in the front yard is a start. If heat stroke continues too far, the next best thing is to call 911 and get an ambulance on the way to rehydrate and cool the runner down on the way to the hospital.

There is a lot of misinformation on the how much water a person needs during a run or just in everyday use. The common standard most of us have heard is to drink eight glasses of eight ounces a day. This started back in the 1940s, when a group of scientists made a recommendation of drinking one milliliter of water for every calorie eaten. For a day of 2,000 calories, that means two liters of water, or roughly 64 ounces, or eight glasses of eight ounces.

The people that put this rough rule of thumb down also mentioned that some of this water intake could come from food sources. Even white bread is 30 percent water, so that would count in that total intake of water.

There is concern amongst some people that drinking tea or coffee will not count, as they are diuretics that cause water loss. This occurs if the person drinks very large quantities of tea or coffee, but a few glasses will not be a problem.

It seems strange, and it may happen only on rare occasions, that the runner may drink too much water. It  usually happens with marathon runners who do not want to end up dehydrated during the run. The water dilutes the blood of sodium, and then the water moves into the cells of the body. The cells of the body can usually tolerate this, but the cells in the brain do this very poorly and can’t expand because of the skull. It basically becomes water intoxication, causing headaches and confusion.

Our systems will adjust to a shortage of water when the blood becomes slightly concentrated and the anti-diuretic hormone reabsorbs more water from the kidneys and returns it to the blood. A basic rule to follow is to drink if you are thirsty, and it really does not make that much difference if you drink 15 liters per day or only one or two liters.

Water seems to be best for this and added “nutrients” such as fiber water, vitamin water, antioxidant water, energizing drink, etc. are of no extra benefit. Some drinks make you feel better because of the amounts of caffeine in them that seems to pick you up. Whether you drink a lot or only a smaller amount, the best guide is to drink the amount that makes you feel good and keeps you out of harms way.

Other than that, pay attention to the warning signs of the problems that may be associated with hot temperatures during your runs.

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