Sex Burns Calories

Thirty minutes of sex burns 85 calories or more. It may not sound like much, but it adds up: 42 half-hour sessions will burn 3,570 calories, more than enough to lose a pound. Doubling up, you could drop that pound in 21 hour-long sessions.

"Sex is a great mode of exercise," says Patti Britton, PhD, a Los Angeles sexologist and president of the American Association of Sexuality Educators and Therapists. It takes work, from both a physical and psychological perspective, to do it well, she says.