If you don't exercise for a long time and suddenly do very intense exercise, your muscles will often ache. There are two kinds of muscle soreness: one is acute muscle soreness, which appears immediately after exercise but disappears quickly; Another kind of pain does not appear immediately after exercise, but appears several hours after exercise or even after a night's sleep, and slowly disappears, taking two or three days to disappear. This kind of soreness is called delayed muscle soreness. Their reasons are not exactly the same. Acute muscle soreness is often caused by excessive exercise and insufficient oxygen supply, which leads to a large accumulation of lactic acid in muscles. Lactic acid is an acidic substance, which can stimulate nerve endings in muscles and produce pain; In addition, the accumulation of lactic acid in muscle will cause local osmotic pressure to be too high, thus sucking up the surrounding water and causing muscle edema. This swelling stimulation is also the cause of muscle soreness. For this symptom, you should massage yourself a little before going to bed the next night after exercise, and taking a hot bath also has certain effect (but soaking in hot water for a long time will make your muscles tired and weak). All these can accelerate the metabolism of the body, so that the lactic acid accumulated in the muscle is gradually transported away from the blood, and the muscle ache gradually disappears. If you don't treat it that day, your muscles will be sore the next day. It's no use doing any treatment at this time, only waiting for it to recover itself. There is no unified view on the causes of delayed muscle soreness. Some people think that muscle fibers tear a little after long-term exercise; Some people think that there is some damage to the connective tissue of muscle. The above two theories have not been confirmed by many experimental materials. Because of the muscle soreness caused by this reason, you can do some stretching and stretching exercises, or do some massage or acupuncture to relieve this muscle soreness. Muscle aches often indicate that your exercise level can't adapt to the current amount of exercise. If you stick to it and exercise regularly, when your whole body function is improved to a new level, you will adapt, and similar exercise will not make your muscles ache. Of course, if these methods can't be recovered, we should consider whether it is a muscle or ligament strain and go to the hospital for examination in time.