To score the most from exercise, you only need to go hard 3 to 4 times a week. But in our more-is-better world, when CrossFit and killer boot camps are the norm, we fear this idea falls on deaf ears.
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The fact is, hitting the gym too often can make you less fit. And, shocker: It can even pack on pounds. "The benefits you want from working out—getting leaner, stronger, healthier—reverse when you don't take breaks," says Holly Parker, Ph.D., a lecturer in the psychology department at Harvard University and a certified personal trainer. Skeptical? Hear us out.
For starters, your muscles aren't designed to kill it 24/7. Exercise creates tiny tears in muscle fiber, and when given a chance to heal, the fibers build up. But without recovery, you won't see those changes in tone or strength, Parker says. You're also stressing out your body if you're crushing Spin or a run day after day. That triggers a surge in the hormone cortisol, says Michele Olson, Ph.D., professor of exercise physiology at Auburn University in Montgomery, Alabama, which studies have linked to belly fat. The uptick in cortisol prevents testosterone, which helps build muscle tissue, from doing its job, so definition suffers, Olson says. Meanwhile, your metabolism hits the brakes to conserve energy. In extreme cases, menstruation goes MIA; again, it's your body's effort to save calories. (As annoying as your period is, it does zap cals.)
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More Isn't Always More
Too much exercise can leave you exhausted, and the extra sweating doesn't always pay off. Research backs this up: When Danish scientists had couch potatoes do either three and a half or seven hours of cardio a week, the group that sweat less lost just as much weight despite burning half the calories during planned sessions. Why? The exercisers who did less actually had extra energy, and scientists think it made them want to move more throughout the day rather than do a face-plant on the couch post-workout.
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