How Many Calories Are You Really Burning?

5 Common Calorie Myths Busted

MYTH: Mile per mile, running and walking burn the same. Not even close. "Running is a more energetic activity, because you're jumping off the ground with each stride," says David Swain, PhD, a professor of exercise science and director of the Wellness Institute and Research Center at Old Dominion University in Norfolk, Virginia. Per mile, running burns about twice as many calories.

MYTH: You need to stay in the fat-blasting zone to slim down. "Women think low-intensity exercise burns the fat from their hips. That's not the case," says FITNESS advisory board member Annette Lang, a New York Citybased private trainer and owner of Annette Lang Education Systems. "If you work out easy for 15 minutes and burn 100 calories, 75 percent may be from fat. If you work out really hard for 15 minutes and burn 200 calories, only 50 percent may be from fat, but you've burned more fat overall and twice as many calories."

MYTH: You can't trust those numbers on the treadmill. Years ago, the calorie-burn indicators on some popular gym machines were reported to be notoriously inaccurate. "These days, they do a pretty good job," says metabolism researcher Gary Hunter, PhD., of the University of Alabama at Birmingham, "especially if you program in your weight."

MYTH: You burn more in the cold. It's true that you incinerate calories when you're shivering. But once you warm up during your workout, you won't use more energy just because it's chilly outside.

MYTH: High-calorie-burning exercises are best. "For many women, what burns the most is the activity they can sustain for a long time, like power walking, hiking, or bicycling," says Ainsworth.