Yoga and pilates enthusiasts tout their workouts with a religious zeal, boasting about the life-changing physical and mental benefits they confer. In the past several years, scientists have been studying what these activities really can—and can't—do for the body:
Yoga: Hatha yoga provides little cardio benefit; power yoga does a bit better, giving the heart the same aerobic workout as a brisk stroll.
Pilates: You may feel the burn with moves like “the hundred,” but your heart won't. A beginner routine offers only a mild aerobic challenge, at the level of a slow walk. An advanced class is better, kicking the heart rate up to that of speed walking.
Yoga: A 50-minute hatha class will burn about 145 calories; a power yoga class, about 250. If your goal is dropping pounds, experts recommend you do a high-intensity activity, like jogging, as well (a 50-minute jog burns about 550 calories). One study found, however, that people who practiced yoga regularly gained less weight during their midlife years than their nonpracticing peers.
Pilates: Expect a 50-minute beginner workout to burn about 175 calories; an advanced, between 255 and 375 calories. You would probably need to do a 45- to 60-minute advanced routine at least four days a week to maintain or lose weight.
Body Strength and Flexibility
Yoga: In a recent study, after eight weeks of doing yoga three times a week, participants boosted their total body flexibility by an average of 24 percent. In a test of strength, they managed an average of six more push-ups and 14 more curl-ups.
Pilates: Bye-bye, crunches—Pilates tends to be better at strengthening the abdominal muscles, and up to 310 percent more effective at tightening the hard-to-target obliques. Overall flexibility should also improve, particularly in the back, hip, and hamstrings.
Yoga: You can achieve inner peace. Yoga has been shown to lower levels of the stress hormone cortisol even after one session. It can also reduce the intensity and frequency of hot flashes by 30 percent, relieves back pain better than traditional exercises, and ease arthritis.
Pilates: It will not lengthen your muscles, as some proponents claim. Muscles can't grow longer, but the back and abdominal strength you build, along with increased flexibility, can help improve your posture, giving the appearance of a taller, leaner body.