Avoid Overheating on the Road

When the organizers of the Peachtree Road Race moved the morning start time from 8 to 7:30 a.m., their intent was to reduce the race’s impact on Atlanta’s rush-hour traffic. But the earlier start for the July 10K run, billed as the country’s largest, also yielded a surprising health benefit.

Following the change, fewer runners showed up in the emergency room, said Dr. Gail Anderson Jr., acting chief of staff at Grady Memorial Hospital, Atlanta. In years past, the hospital treated “30, 40 or 50 patients,” Anderson said, many for heat-related problems prompted by strenuous exercise in Atlanta’s muggy, hot summer climate. This year, only a handful of the 50,000 runners were treated, he said.

The earlier start made all the difference, said Penny Kaiser, assistant race director. At 7:30 a.m. in early July, Atlanta’s temperature can be a pleasant 70 degrees. But “it can creep to the low 80s by 10,” Kaiser said.

Anderson offered the race story to illustrate the wisdom of his advice to summertime travelers: Make simple changes and take small precautions to keep cool and avoid heat-related illness on the road.

Whatever their destination, travelers should consider both temperature and humidity, Anderson advised. Pay attention to heat indexes, which take both parameters into account. There are a variety of heat scales, but generally, Anderson said, “the higher the humidity and the higher the temperature, the greater the risk.” (For more information on heat indexes, call the American Council on Exercise, 800-529-8227.)

One heat index, used by the San Diego-based American Council on Exercise, a nonprofit organization committed to promoting physical activity, lists air temperature on one side of the chart and relative humidity on the perpendicular side. By converging the two lines a “heat sensation” number is determined. For example, if the temperature is 90 degrees and the humidity 30%, the heat sensation, as indicated on the chart, is 90 degrees--and there is a risk of heat cramps.

If the temperature is 95 and the humidity 50%, the heat sensation temperature is 107 degrees, which is associated with the threat of heat cramps, heat exhaustion or heat stroke.

The chart illustrates that there is a scientific basis to the commonly held notion that dry heat is more tolerable than humid, Anderson said. “In a dry climate, you can sweat more easily.” Evaporation of sweat, an important component of body cooling, occurs more readily in dry climates because the air has less moisture.

Travelers taking short vacations that require visits to hotter, more humid climates than they are accustomed to shouldn’t expect to adjust completely, or to exercise intensely in the new environment, said Richard Cotton, exercise physiologist with the American Council on Exercise. A Southern Californian visiting Washington on a two-day trip, for example, needs to “remember they won’t acclimatize,” Cotton said. It can take four to six weeks, Anderson said, to completely adjust to a new environment.

To ease the transition, travelers participating in athletic competitions in other cities should try to get there a few days before the event and drink plenty of fluids, either water or sports drinks, such as Gatorade. Drink eight ounces of water 20 minutes before workouts at the new destination, Cotton said. Then try to drink four ounces every 15 minutes while working out. Reduce or eliminate alcohol consumption, he added, since it can act as a diuretic.

Travelers who visit higher elevations often have fewer heat-related problems, Cotton noted, since temperatures drop. “From Denver to Evergreen [Colo.], for example, the temperature can drop 10 degrees or more,” he said.

Wearing white or light colors and a hat can help the body stay cool. Eating a high-carbohydrate diet also is recommended.

Avoid salt tablets, Anderson advised, unless your doctor recommends them. Salt tablets were routinely prescribed in the past to replace salt lost in sweat but a better idea, Anderson said, is to drink plain water or sports drinks.

Heat related problems can include cramps, exhaustion or heat stroke. The very young and the elderly are most at risk. Cramps, the result of dehydration and the loss of electrolytes, such as sodium and potassium, most often strike leg and abdominal muscles but may progress to heat exhaustion. Symptoms of heat exhaustion include weakness, nausea, vomiting, fatigue and thirst. Should any such symptoms occur, “Get out of the heat,” Anderson said. “Get medical help.”

Heat stroke, the most serious heat-related problem, is marked by a change in mental status. Chills, weakness or nausea might be the first symptoms a victim notices. Prompt medical attention is vital.

The Healthy Traveler appears the second and fourth week of every month.