As spring gives way to summer and temperatures rise across the country, it’s natural to want to take our exercise routines outside. A bike ride in the sunshine, an afternoon hike, or a crisp morning run are the kinds of pleasures that define the season.
But as with most pleasures, being active in the summer is not without risk. Too much sun exposure can prematurely age your skin (or cause skin cancer), while a heat injury like dehydration, heat exhaustion, or heatstroke can land you in the hospital (and potentially kill). That doesn’t mean you have to give up exercising in the summer months — but take precautions to prevent injury.
What Puts People at Risk?
Higher air temperatures are, naturally, a major cause of heat injury, and one good way to protect yourself is to exercise in the early morning or late evening, when temperatures are cooler. Other contributing factors include the relative humidity in the air and the heat your body produces as you exercise.
These factors are balanced by the body's ability to get rid of heat. We shed heat through our skin, like a radiator, and by breathing and sweating. When the humidity is high, sweat can’t evaporate and our core temperature rises, which is why it’s especially important to be mindful of heat risks in more humid climates. Keep an eye on the weather reports, and if the humidity is higher than usual in your area, make sure you compensate for that — slow down, or move your workout indoors.
Sweat is the exerciser’s friend. To ensure that your body can do this crucial task efficiently, stay hydrated, wear light, breathable clothing, and leave more skin exposed to the air.
Acclimating to higher temperatures can also help athletes perform better and more safely in the heat. As the weather gets hotter, moderate your activity by cutting down the time and intensity of your outdoor exercise, then slowly build back up. In his book Nutrition for Health, Exercise and Sport ¸ Mel Williams notes that when you acclimate to higher temperatures gradually, your body makes several important physiological adjustments that help it dissipate heat, including producing more sweat and increasing blood flow.
E. Randy Eichner, M.D., writing in the online journal Sports Science Exchange, says that a major risk factor for heat injury is “overmotivation.” In other words, pushing yourself too hard when it’s too hot is definitely not advisable. Listen to your body — if you feel weak, dizzy, headachy, or exhausted, stop exercising, find shade, and drink some fluids.
If you suspect your workout partner has heatstroke (symptoms include fever, confusion, fainting, nausea, rapid heartbeat, shallow breathing, and skin that's hot to the touch), call 911 immediately and get her out of the sun. Remember that children, the elderly, and obese people are at greater risk to heat illnesses.
Hydrate, Hydrate, Hydrate
Dehydration can impair your performance and lead to heat injury, so it’s important to consume enough fluid. For exercise sessions lasting about an hour, Williams recommends drinking at least two to three cups of fluid an hour beforehand and one cup every 10 to 15 minutes during your exercise session. If you’re going to be out for longer than an hour, make sure to continue to drink every 10 to 15 minutes, and eat a small snack or have a sports drink to replace the electrolytes lost through sweating. Drinking only water or too much of any fluid throughout very prolonged exercise sessions (three hours or more) can lead to dangerous imbalances in your system.
After the exercise session, continue to drink fluids to replace what you lost to sweating. You can figure out how much by weighing yourself before and after and drinking accordingly: over the next few hours, drink at least two cups of water (16 ounces) for each pound lost. Monitor the color of your urine between workouts — if it’s the color of lemonade or paler, you’re good to go. If it’s the color of amber ale, start drinking (but not beer — almost all beverages will hydrate you, except those containing alcohol).
With the thinning of the ozone layer, more solar radiation is hitting our planet and the incidence of skin cancer is rising. The Centers for Disease Control recommends a multipronged approach to sun protection.
First and foremost, remember that shade is your ally. A workout under the trees or a trail run through a forest will minimize the rays hitting your skin. When you shop for sunscreen, look for both UVA and UVB protection and a sun-protection factor (SPF) of 30 or better. Apply it liberally — at least an ounce per application. Reapply every two hours or after a sweaty workout.
Regular clothing provides enough sun protection for most of us, but if you are very fair and prone to sunburns, sun-protective clothing can give you an added measure of defense against the rays.
There are a million excuses for skipping a workout; don’t let the summer weather be one of them. You can exercise safely outdoors in the summer, as long as you take it easy and take precautions.