Breast tissue is mainly fat; to reduce it, you must burn more calories than your body uses daily. This will slim your entire body including your bustline. In addition to a sensible diet, exercise can contribute to the caloric deficit that's needed to trigger weight loss; to lose one pound a week, a daily deficit of 500 calories is needed. Both cardio and strength training should be part of your workout routine.
Cardiovascular Activities to Burn Calories
Cardio burns calories and contributes to the daily deficit that's needed to lose weight. The American Heart Association suggests doing at least 150 minutes of moderate cardio a week. In one hour, a 150-pound person can burn about 240 calories bicycling at a speed of 6 mph; 400 calories playing tennis; 440 calories walking at a speed of 4.5 mph; and 750 calories jumping rope.
Strength Training to Preserve Muscle
Strength training preserves and increases muscle tissue, which promotes caloric burn and can take inches off your body including your bustline. The AHA favors full-body strength training at least twice a week. In addition to working your back, hips, shoulders, abdomen, legs and arms, target your pectoral muscles underneath your breasts with exercises, such as knee, wall, or full pushups, bench presses, dumbbell flyes, cable crossovers, and dips. Aim to tone your muscles under the fat, and avoid using too much weight, because this can increase your muscle size, which is not what you're aiming for.