Knowing when – and how – to work out when it’s hot outside can help you avoid dehydration and heat stroke.
Now that the weather has warmed, you can relocate your fitness routine from the gym to the park or backyard. Just keep an eye on the temperature before you head outside. When the temperature is high and you’re working up a sweat, heat exhaustion and heat stroke become real worries.
Your body has a built-in cooling system to keep you healthy and comfortable in hot weather. As you sweat, the liquid evaporates from your skin, cooling you off. Your heart also beats harder to shuttle more blood to your skin’s surface so sweat can cool it down. That blood has to be diverted away from other areas, like your hard-working muscles.
If your body’s cooling system can’t keep pace with the outside temperature and the intensity of your workout, or you don’t drink enough fluid to replace what you’ve lost through sweating, you could become dehydrated and eventually develop a heat-related illness like heat exhaustion or heat stroke. Too little fluid in your system can also cause painful muscle contractions, called heat cramps.
Here are a few tips to help you stay cool – and safe – during those warm weather workouts.
Temperatures are lowest before the sun rises, making pre-dawn the best time for outdoor exercise during the summer months. Avoid outdoor fitness during the peak heat hours of 10 a.m. to 4 p.m. “If your schedule will not accommodate an early morning workout, wait until at least 5 p.m.,” said Stacey Snelling, PhD, associate dean of the American University School of Education, Teaching, and Health.
On some summer days the mercury can soar even before dawn. Humidity only adds to the oppressive atmosphere. Check your local weather report. If the temperature is above 80 degrees Fahrenheit and the humidity is 80 percent or higher, skip your workout or move it indoors to be safe.
Cotton might be soft, but it soaks up sweat and can weigh you down in the heat. To keep your body dry and cool, wear lightweight, synthetic, moisture-wicking fabrics that pull sweat away from your skin. Lighter-colored fabrics reflect light and will keep you more comfortable than dark ones. Choose an SPF fabric to also protect your skin from the sun’s burning rays.
You can get dehydrated very quickly on hot days. About 20 to 30 minutes before you go outdoors, drink about 8 to 12 ounces of water. Keep replenishing fluids as you work out. “Drink enough water to replace what you lost during your activity,” Snelling advises. If you’re exercising at a high intensity, switch to a sports drink to replace lost electrolytes, too.
Take it slow
The heat and humidity will make your heart pound, even while you’re at rest. Don’t overdo it or you could overtax your heart. Slow down your pace to accommodate the warmer temperatures. Once your body starts getting used to the weather, you can gradually increase the intensity again.
Once you’re done working out, wrap up with a five- to 10-minute cool down. Walk slowly to bring your heart rate back to normal and do a few static poses to stretch out your muscles before heading home.
Watch for warning signs
If during your workout you start to feel dizzy, nauseated, weak, or you’re sweating profusely, stop. You’re probably losing too much fluid. If you don’t restore those fluids, you could develop heat exhaustion, which can turn into a life-threatening heat stroke without prompt medical attention. Get inside right away to cool off and have a drink of water. If the symptoms continue, call 911 or go to your local emergency room.
March 30, 2020
Janet O’Dell, RN