Can I Consider Sex a Workout?

Find out which muscles you'll tone and how many calories you'll burn in the bedroom. 

Question: "Can I consider sex a workout? (Please say yes!)"

Answer: You can't exactly substitute a romp in bed for a three-mile run, but sex does offer some fitness benefits, says Laura Berman, PhD, author of The Passion Prescription: Ten Weeks to Your Best Sex -- Ever! (Hyperion, 2006). "You'll strengthen your quads, hamstrings, and abs and burn calories," she says.
Of course, how many calories you burn depends on the duration and, ahem, vigor of the activity. A moderate 20 minutes will burn only about 28 calories, 32 at a more energetic rate -- but you can burn close to 100 calories if the fun lasts for an hour.