You should be exercising to torch the competition, not spontaneously combust. Tell that to the approximately 4,300 men who show up at emergency rooms each year with heat-related maladies. An athlete who’s too focused on chasing personal records may not listen to his body’s internal signals to slow down, says Col. Francis O’Connor, M.D., a professor of military and emergency medicine at Uniformed Services University of the Health Sciences.
As you exercise, your muscles generate metabolic heat that ramps up your core temperature. The trouble starts when you can’t cool down properly because of other factors—like intense activity, hot and humid weather, lack of proper hydration, or wearing the wrong gear. Once your temp reaches the 103° to 105°F range, you may experience headache, dizziness, nausea, lightheadedness, or extreme fatigue. Keep pushing, and you might suffer exertional heatstroke (i.e., you’ll become feverish and collapse), which could be life-threatening.
Before you end up in the ER, use these three strategies for keeping your cool at all times.
Maintaining a lower core temperature will mean less fatigue. That’s way more fun to do than you might think. According to a study in the Clinical Journal of Sports Medicine, athletes who ate ice slushies during exercise were able to run comfortably for up to 15 minutes longer than those who drank cold water. Try this recipe from endurance coach and exercise physiologist Matt Dixon of PurplePatch Fitness: Blend enough ice to fill an insulated sports bottle, and pour any sports drink over it. On long runs, create a loop that’ll allow you to circle back to your bottle at intervals, says Douglas Casa, Ph.D., a professor of kinesiology at the University of Connecticut. And drink water too. You may need to consume 1 to 2 quarts of fluid per hour, he says.
Even if you’re rocking the latest breathable, water-wicking performance fabric, at some point your shirt will become so saturated that it’ll trap your body heat instead of helping you vent it. Remember: It isn’t the sweat that cools your body; it’s the evaporation of those beads off your skin. Once the garment feels heavy, it’s time to switch it out. “This will enhance the evaporation of sweat, improving your heat tolerance and your cooling response,” Casa says.
If you’re burning up, it’s time for a primitive protocol: cold-water immersion. Fill a kiddie pool with several bags of ice and get in. Frigid water will lower your core temperature about 1 degree every five minutes, Casa says. At hot races, staff may have such tubs set up at the medical tent at the finish. If you’re in a remote area, pack a cooler with ice and water in the back of your car to dunk your arms and legs in. Feeling frosty is better than being out cold.