According to experts, climbing stairs upstairs is equivalent to doing aerobic exercise, which can exercise cardiopulmonary function, and at the same time can exercise the leg muscle groups, can play a certain exercise effect. But when going down the stairs, the knee and ankle joints must bear the entire The weight of the body, repeated this movement, will artificially increase the amount of activity of these joints, the intensity of compression will increase sharply, the possibility of joints being worn will increase, which is not good for the body. What is the correct understanding of this text? ['Regular climbing stairs can achieve exercise effects.', 'People with heart problems should often climb stairs.', 'Downstairs helps joint recovery.', 'Stairs should be accelerated.']