Fitness instructors have exercised a lot for many years, and the muscles increase and consume fat, while the fat decreases and the meat tightens. This is a dynamic balance, the total amount of muscle+fat is constant, and people burn fat during exercise. The less fat, the more muscles.
In addition to building muscles, exercise can also make the skin firm. Exercise helps to activate cells in the body and promote metabolism. Not only good for the skin, but also good for the inside of the body. It can make the body organs move normally. Exercise can slow down the aging of the body. Regular exercise is the best, but it is a long-term and continuous process. This is only an auxiliary effect on aging. Don't pursue speed too much. If slow aging can also be regarded as firming the skin, it can also be regarded as a way.