Shortcuts to shape-up your body fitness

The cheat: Resting longer than the prescribed time during a circrut
The verdict: Go forit
> Many circuits call for short rests-usually 30 to 60 seconds-to keep your heart rate high enough to produce a cardio benefit (read: calorie burn). But if you're really struggling after a tough set, tack on an extra 30 seconds of rest, says Rebecca Stephenson, board-certified women's health specialist in physical therapy at Harvard's Brigham and Women's Hospital. It will give you (and your muscles) enough of a breather to complete the next set with perfect form without compromising your calorie burn.
The cheat: Exercising in the morning when you re deadtired
The verdict: Bad idea
> Ifyou truly didn't get cnough shut-eye (you rolled in at 3 a.m. or you were up all night
with a crying baby), crawl back under the covers. A study found that when dieters were sleep
deprived they lost less body fat and morelean muscle mass than when they tallied more Z's.
What's more, exercising when you're too drained can take your focus off proper form, upping
your risk ofinjury.
If you're just feeling groggy, get your butt out of bed by committing to do half of your
workout, suggests Michele Olson, Ph.D., a professor of exercise science at Auburn Universityin Alabama. Chances are, you'II pick up steam as you go and bang out the whole thing. "Knowing
that you can cut it short will get you out the door, which is the hardest part:' she says.