You definitely need to gain muscle and stay healthy. If you go to this thing three or four days a week, you can be advised not to drink carbonated drinks before and after fitness, but to drink functional drinks, such as Red Bull! There are also some muscle-strengthening protein powders that can be washed after fitness. Taobao sells animal protein drinks. Muscle gain effect is fast ~ eat an egg and an apple every day! I don't know if you have a sitting rowing machine or a sitting chest expander for exercise, but they are all suitable for your current price range ~