Train at 5 a.m.
"The world is so full of promise when viewed at sunrise," Brookner says. True, but equally important, it's a little cooler. Put in your miles before the sun is high.
Cross-train indoors
Build your cardio base while taking a break from the heat and humidity by swapping an outdoor bike ride for an inside Spin? class.
Do speedwork on a treadmill
Intensity of exercise is a major factor in heat distress—the harder you run, the higher your risk. Plus, when you try to run fast in extreme heat, Brookner points out, "your perceived effort almost always exceeds your actual effort." To make your intervals safer and more productive, stay in and run as fast as you like in air-conditioned comfort.
Ease into the heat
Do a slow, two- to three-mile walk or very easy run at the hottest part of the day two times per week for three or four weeks to acclimate to the heat. "It makes the morning run feel cool," says Brookner.
Have a hydration plan before you start
Know where your water stops are, either by plotting your runs in areas that have water fountains or by stashing bottles at strategic points along your route ahead of time. Also get in touch with local running clubs and training groups to find out where they might put out jugs, so you can share.
Don't just drink the water
A combo run-and-swim workout is perfect on really hot days. One of Brookner's favorites is a three-mile run from the Cocoplum traffic circle to Matheson-Hammock Park in Coral Gables, Florida. There, he and his buddies dive into the cool, clear waters of the nearby lagoon, swim for 15 to 30 minutes, get out, and run back. You can re-create this duathlon anywhere there's a body of water, or even a local pool.
Plan to race in cool temperatures
For Brookner, registering for a fall marathon "up north," such as Marine Corps or New York, basically guarantees relief from the heat. And the cooler race temperature is like a key unlocking the sultry shackles that have bound his feet throughout the summer. "When I show up in New York for the marathon in November and it's in the 70s, the New Yorkers are all like 'ugh,' and I'm saying, 'Bring it on!'"