With climbing temperatures and endless sunshine, summer is the perfect time to take your workout outdoors. But exercising al fresco does have its caveats. Distances seem longer and hills appear steeper. In the heat, a simple jog can be a grueling test of endurance with potentially fatal consequences. According to the Centers for Disease Control and Prevention, heat stroke kills approximately 300 people each year.
A recent study from New Zealand appears to have a solution. Researchers found that all you may need to beat the heat is an ice-cold slushie, available right at your local convenience store. When young male recreational athletes downed one of these tasty treats they added an average of 10 minutes to their usual water-only 40-minute runs.
Not everyone is convinced that the answer to our summer fitness woes can be found in an chilly cup of food coloring and high-fructose corn syrup. "You're much more likely to get a headache than be able to run longer," says Michael Sawka, chief of Thermal and Mountain Medicine at the U.S. Army Research Institute of Environmental Medicine. "Drinking a slushie isn't going to provide any sort of protection against heat stroke. The risk is much too complicated to be solved simply by absorbing a little bit of heat and having a body temperature slightly lower for a few minutes."
For the average exerciser going out for a 3-mile run in 80-degree weather, in fact, guzzling a slushie is more likely to hurt rather than help athletic performance. "As long as you're hydrated and don't have any pre-existing conditions, you'll be just fine," says Craig Crandall, an exercise physiologist at the University of Texas Southwestern Medical Center who studies the effects of exercising in the heat. "If you are in a select population, like a highly fit cyclist exercising for two hours or longer in 100-degree weather, a pre-cooling method may be something [you] want to consider."
But for the majority of us, tried-and-true recommendations for exercising in warm weather will do the trick. Here are Sawka's and Crandall's top 5 methods for staying safe outdoors this summer.
Tip 1: Stay hydrated. And that doesn't mean drink a slushie. For the average person, who is likely to get plenty of sodium and potassium through his or her diet, water works fine. The key is hydration before and throughout exercise. You can easily measure how much water is ideal, says Crandall, by weighing yourself before and after your workout. The difference will tell you how much sweat was lost and how much fluid needs to be replenished.
Tip 2: Exercise early in the morning or late in the day. To avoid intense heat, plan your runs during either of these two windows. The best method for improving heat tolerance and decreasing the risk of heat illness is to gradually acclimate yourself to exercising in hot environments, a process that takes 7 to 14 days. "Don't go out and run for an hour in 100-degree weather right at the onset," says Crandall. "Give your body a chance to acclimate and work up to exercising in those conditions."
Tip 3: Dress comfortably. Wear light, loose-fitting clothes. Synthetic fabrics like polyester, nylon, and Lycra that absorb sweat are best for exercising in the heat, says Sawka.
Tip 4: Be aware of your prescriptions. Many prescription and over-the-counter medications can increase the chance of heat-related illness by promoting heat storage or impairing sweat glands, says Sawka. Antipsychotic medications, antihistamines, antidepressants, and some muscle relaxants are just a few that generally interfere with sweating. Individuals taking these medications should be especially wary and monitor their body temperature closely when exercising in the heat.
Tip 5: Be safe, not sorry. Every individual's susceptibility to heat is different. "There are people who lose a lot of electrolytes through their sweat, and some who don't lose as much," says Crandall, who notes that most of us don't know which group we are in. "That's why it's so crucial to pay attention to your body and take extra precautions in the heat."