While weight training has no direct influence on the size of your breasts, it can boost the size of the pectoral muscles that are beneath the breasts. The weight training, and the resulting impact on your chest, will simply give the appearance of larger breasts.
Can working out make your breasts bigger?
The chest muscles beneath the breasts and the connective tissue within the breasts support their weight but do not contribute to their size. Therefore, working out does not directly affect the breast tissue, but exercising and strengthening the surrounding muscles can enhance the appearance of the chest.
Do chest workouts make breasts bigger or smaller?
Chest exercises alone will not make your breasts smaller. These exercises serve to strengthen your pectoral muscles, or the muscles just beneath your breasts, lifting your bustline and making your breasts appear larger.