2. Pay attention to walking moderately, especially don't hurt the knee joint. This is a "damaging" organization, that is to say, no matter how you exercise, his nature will not change, but will only wear out slowly. For example, the elderly think that mountain climbing is exercise, but it is actually wrong. Old people who often climb mountains have knee injuries, and many people need surgery. Just like the lamp tube of a projector, it is a consumable. The longer it is used, the shorter its life will be. Remember, remember.