Why it works to reduce stress: Circuit training alternates weight-training moves with cardio, with short rests in between. The result is a high-intensity workout that offers the same benefits of longer exercise sessions in less time (30 minutes or less). It’s short, sweet and pumps up your body’s endorphin level, which improves your mood. Better yet, you don’t have to stress about finding lots of time to fit a workout in.How to do it: Onepopular circuit training program is Curves, the national chain that uses musical cues to guide members to switch stations during a 30-minute exercise circuit. For an even smaller investment, check out fitness diva Kathy Smith’s Super Slimdown Circuit DVD. Why it works to reduce stress: Pilates is a series of exercises that emphasizes body awareness, core strength and proper alignment. “With its equal focus on strengthening and lengthening muscles, Pilates creates a physical harmony that simply doesn’t allow stress to take hold as easily,” says Ellen Barrett, fitness expert and creator of the Pilates DVD Slim Sculpt. Like yoga, the mental concentration required for Pilates “zaps you into the moment, leaving little mental space for worrying,” Barrett says. Finally, Pilates is known for reducing back and neck pain, another side effect of stress. How to do it: Pilates can be performed on a machine known as “The Reformer" – typically available only in Pilates studios – or on a mat on the floor (logically labeled “mat” or “floor” Pilates on gym schedules). If you’d like to get started at home, check out the DVD Pilates for Beginners with Kristin McGee. 9. Tennis Why it works to reduce stress: A great cardio workout, tennis can prevent many stress-related conditions, such as high blood pressure and heart disease. And because you can’t play tennis alone, the sport keeps you connected to others – a key component of stress reduction. “Working out on the tennis court triggers your brain to release endorphins into your body. Those are the biochemicals that produce euphoric feelings of peace and satisfaction,” says John Sklare, Lifescript’s Personal Coach and a tennis coach. Check with your doctor before beginning any fitness program.