The Dallas Morning News Every summer, well-meaning fitness magazines and newspaper articles warn that our brains will melt like ice cream...

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The Dallas Morning News

Every summer, well-meaning fitness magazines and newspaper articles warn that our brains will melt like ice cream if we exercise outside in the heat of the day.

Triple-digit temperatures and sauna-thick humidity are facts of life in some places. But it’s a myth that you have to limit your outdoor pursuits because of them. Athletes of all levels have learned to embrace the hottest hours of summer, like those training for Texas’s White Rock Marathon in December.

“For some of our runners, our Saturday morning runs are the only mornings they’ve run the entire week,” says Luke’s Locker footwear specialist Chris Greene, who’s also a half-marathon coach for Luke’s Fit program. “Many run after work, the hottest time of the day.”

Those runners are acclimatized, which is the first step for getting used to the heat.

How to acclimatize: Acclimatization simply means ratcheting down your outdoor workout to a lower, sustained effort for at least five days to a couple of weeks, incrementally building up your heat tolerance, says cardiologist Benjamin Levine, director of the Institute for Exercise and Environmental Medicine, which is a collaboration between the University of Texas Southwestern Medical Center and Presbyterian Hospital of Dallas.

Bike slower than normal. Walk if you normally jog. Jog a shorter distance than you typically run. Keep your body temperature down by taking a lot of breaks in the shade.

“It’s amazing how well the body learns to acclimatize. But at first, it’s dangerous,” Levine says. “The more intense and harder the exercise, the greater amount of heat is generated.”

Which means there are precautions to take during this heat boot-camp period. Any time you feel lightheaded or extra fatigued, pause and seek shade until you cool off, he says. Repeat as needed until you build up tolerance to the heat.

This goes for even the fittest athletes. Ultra runner Christine Tokarz of Pottsboro, Texas, went toe-to-toe with the state’s heat for the first time during a race last year in Pedernales Falls State Park.

“I was a total novice at summer running in Texas. At seven miles, my legs felt like total tree trunks and I couldn’t see straight,” says Tokarz, executive director of All Saints Camp and Conference Center on Lake Texoma.

Now that she’s acclimatized, Tokarz loves running in the heat. She says it makes her feel like she’s getting a thorough workout, plus it helps condition her body for races in higher altitudes.

Acclimatized or not, it’s smarter to choose the treadmill over the trail if the weather gets extreme.

“Let’s say for example, it’s 105 degrees outside and humid. How are you ever going to cool down?” Levine says.

Hydrate: Important to keeping your body from overheating is hydration. Recommendations for daily fluid intake abound, starting at 64 ounces to double that. But don’t drive yourself crazy with numbers, Levine says.

“The problem with a general guideline is that it’s fine for the average person, but it really fails most people,” he says.

Everyone’s needs are different. Choose a guideline, “play” with it and learn what works best for you individually, he says.

Just don’t go hydration-crazy. In 2007 the American College of Sports Medicine changed its previous stand, which said to drink all the water you possibly can during a workout. It now warns that too much water can cause a sodium imbalance in the body.

“Athletes need to listen to their thirst. One of the biggest myths is that thirst is not a guide,” Levine says. “If you drink a lot when you’re not thirsty … you can overhydrate. Yes, you can get dehydrated before you become thirsty, but not dangerously so.”

Levine recommends the sweat rate test to track how much fluid to replace during a workout: Weigh yourself without clothes before and after an hourlong workout; add the amount of any fluid you drank from your weight loss difference. That’s the amount of fluid you lost through sweat.

You’ll have to repeat the test for different conditions, such as change of season or time of day. Also note that as you become acclimatized to the heat, you will sweat even more.

Luke’s Fit program coaches tell their participants to drink 16 to 20 ounces of water before training, carry 20 ounces of water on the run to sip every 15 minutes and switch to an electrolyte sports drink after the first hour.

In addition to sports drinks like Gatorade or HEED, you can also replenish your body’s lost sodium with salty snacks, Levine says.

Tokarz tries to consume 100 liquid calories an hour on runs. “If I’m doing some real long miles, I carry a couple of bucks to stop and get (a sports) drink somewhere in the middle of the run.”

Greene stays hydrated by using an ergonomic, insulated handheld water bottle that keeps his fluid chilled.

“The heat doesn’t bother me,” he says. “But I can’t work out in the cold. The cold is another story.”

Does caffeine count?

What about the common thought that caffeinated drinks dehydrate you? Water is water, cardiologist Benjamin Levine says, and caffeinated drinks such as coffee and tea do, in fact, help hydrate your body throughout the day.

Caffeine is only a modest diuretic. “Caffeine will not harm anyone exercising outdoors,” he said. What matters most in this heat is “to make sure your body temperature is under control.”

So, it’s OK to crack open a Red Bull during halftime at your soccer match? Technically, yes. “It might drive you to exercise harder, though, because it is a stimulant drug,” he said. “In the heat, it could overcome common sense. Everything in moderation.”