After the winter many of us suffered through, now you're complaining about the heat? Yes, it slows your pace—by 1.5 to 3 percent for every 10-degree jump above 55 degrees F, in fact. And it can sap your enthusiasm. But by training through scorching temperatures, runners reap a performance boost come autumn.
In hot weather, one way your body tries to cool itself is by sending blood to the skin's surface, where the blood's heat dissipates into the air, says Janet Hamilton, a Georgia-based running coach and exercise physiologist.
This cooling action diverts blood (and its run-fueling oxygen) away from working muscles. To satisfy the opposing demands of cooling and exercising, your body makes more blood. Once the mercury drops, your muscles enjoy this surplus. "You feel like you can fly, like Peter Pan," Hamilton says. "If you're on the cusp of a PR, heat training can be the factor that closes the gap."
Even if you're not gunning for a personal record, summer brings a host of advantages that you'll miss once the snow starts falling. Next time you're tempted to grouse about hot weather, consider summer's perks.
Summer's extended daylight makes morning and evening runs more appealing. "People who may not feel safe running in the dark can find a daylight time that doesn't interfere with work," says Hamilton. This exposure to sunlight also makes it easy to get your daily dose of vitamin D. (See Bright Outlook, page 45, for more information.)
Since getting out the door feels harder in the dark, a bright sky means you're less likely to skip summer workouts, says Ken Mierke, a Washington, D.C.-area coach who developed the Evolution Running program. You can even experiment with running twice in one day, say 20 minutes in the morning and 20 minutes at night. "Twice-daily running can be helpful when work or family commitments limit big blocks of time," Hamilton says.
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