Dan Rayfield Indian Trail Master Naturalist
Even though the calendar says it is still technically spring, here in Texas summer begins on June 1. For Master Naturalists, Master Gardeners and all folks who like to be outdoors, it is time for what I call “summer hours”. That means it is time to begin our outside adventures early and then get out of the heat before it gets too intense. This is not just a matter of comfort. Exercising, whether for work or play, during periods of high heat can lead to serious health consequences.
There are several levels of heat-related illness. Heat cramps is the most common and least dangerous. Your muscles react to the loss of fluids and go into spasms. Next in the hierarchy of heat-related illnesses is heat exhaustion. The most serious condition is called heat stroke. It is important to realize that there is no clear distinction between heat exhaustion and heat stroke. Heat stroke is simply more severe than heat exhaustion. All heat-related illnesses are caused by the body’s inability to regulate its internal temperature by the evaporative cooling effect of perspiration.
Symptoms of heat-related illnesses include nausea, fatigue, headache, weakness, vomiting, muscle cramps and dizziness. Obviously, when these symptoms occur it is time to find shade and begin adding fluids. For many people, by the time symptoms appear you are well on your way to a heat-related illness. Don’t think you can just sit down for a while, drink a glass of water and then go back to work. If you have those symptoms it is time to call it a day, go inside and focus on rehydrating.
However, rather than trying to cope with the results of a heat-related illness, it is better by far to prevent them from occurring. Fortunately, the US Army has done extensive research in the area of prevention. Their most recent recommendations are rather surprising. Since we are already in a Texas summer, let me jump to the Army’s heat category 5, which is a heat index above 90 degrees. During those conditions, while performing what the Army calls “easy work”, you should work for approximately 50 minutes and rest for 10 minutes out of every hour and drink one quart of water per hour. If you are performing what the Army calls “moderate work” you should only work for 20 minutes and rest for 40 minutes per hour while still consuming one quart of water. An example of what the Army considers easy work would be walking on a hard surface at 2.5 MPH with a 30 pound load. The Army considers moderate work to be walking on a hard surface at 3.5 MPH with a 40 pound load. Now keep in mind that these recommendations are for young, fit soldiers. I am guessing that the recommendations for those of us no longer young and less than totally fit would be more along the lines of “get out of the heat you crazy person.”
Summer is a wonderful time of year. Our gardens are growing. Baseball is in full swing. The kids are out of school. (Well, two out of three isn’t bad.) Just remember to take it easy and consider switching to summer hours. Work in the morning if you can. Work in the early evening if you have to. Drink plenty of liquids. And remember the old Indian saying from the British colonial period. “Only mad dogs and Englishmen go out in the noonday sun.”