The purpose of fitness is to make the thin stronger and the fat thinner. Fat and muscle reach the ideal ratio.

So fitness can get thinner and thinner, only for fat people, but it will never get thinner unless you exercise unreasonably.

So, rest assured to engage in fitness exercises and dispel your original concerns.

Supplementary answer:

Whether muscles can become strong or not mainly depends on the nutritional absorption and social intake of muscles after exercise. N- nitrogen protein is a very needed nutrient for muscles, which can directly stimulate the growth of muscle bundles. It mainly exists in animal protein. Eating more meat and eggs can help muscles grow well. By the way, the gym has N- nitrogen protein products, non-chemical green drugs, granules and a variety of flavors. You can buy some to try, but you must follow the instructions.