Know this: “You’ll be able to comfortably work out longer and harder if you’re cool,” says Len Kravitz, PhD, coordinator of exercise science at the University of New Mexico. “Being too hot stresses your body out, so you don’t perform as well.” Translation: You burn less fat.

Do this: When exercising at home, put a fan in front of your workout area. Hitting the gym? Wait to use the treadmill that has a fan built into the console.

Know this: “Wearing a heart-rate monitor makes it easier to burn more body fat by showing just how hard you’re really working,” Kravitz says. “Keeping your heart rate in the right zone prevents you from slacking off, so you make the most of every minute.”

Do this: Invest in a heart-rate monitor and wear it every time you exercise. We love Life Fitness’s new Dual Watch and Heart Rate Monitor ($60; at CVS stores nationwide). It’s simple to program and use. It doesn’t require an uncomfortable chest strap—just touch the face with your fingertips. And it comes in a variety of sizes, too.

Know this: Warming up. (…)

Do this: Warming up. (…)

Know this: Pacing. (…)

Do this: Pacing. (…)

Know this: Smaller workouts. (…)

Do this: Smaller workouts. (…)

Know this: Psych yourself. (…)

Do this: Psych yourself. (…)

Know this: Short breaks (…)

Do this: Short breaks (…)

Blast Off Fat (Way) Faster (Health.com)