The human body requires energy to exercise. If the energy comes from aerobic metabolism (oxidation reaction) within the cell, it is aerobic exercise; but if the energy comes from anaerobic enzymes, it is anaerobic exercise. During aerobic metabolism, one gram of glucose is fully oxidized to produce 38 ATP (energy units), while during anaerobic enzymation, one gram of glucose produces only two ATP. aerobic exercise produces water and carbon dioxide, which can be easily excreted through respiration and is harmless to the body. However, during enzymation, a large amount of intermediate metabolites such as pyruvate and lactate are produced, which cannot be eliminated through respiration. These acidic products accumulate in the cells and blood, and become “fatigue toxins”, which will make people feel tired and weak, muscle aches and pains, as well as respiratory and heart rate increase and cardiac arrhythmia, and in severe cases, acidosis and increased liver and kidney burden. So after anaerobic exercise, people are always tired, muscle pain to last a few days to disappear. How to master the essentials and scale of aerobic exercise? 1, warm up before exercise each exercise before the need to have a warm-up process that is the preparation activities, activities joint ligaments, stretching limbs, waist and back muscles. Then start with low-intensity exercise, and gradually enter the appropriate intensity of the exercise state. 2, close to but not more than the “target heart rate” in general, the target heart rate is 170 – the value of age. If you are 60 years old, the target heart rate is 170-60 = 110 (beats / min). When you exercise, you can always count the pulse, heart rate control in 110 times / min or less, exercise intensity is appropriate, of course, this refers to healthy athletes, weak and sick people are not included. If the exercise heart rate is only 70 to 80 times / min, far from the target heart rate, it means that it has not reached the aerobic exercise standards. 3, self-perception self-perception is an important indicator to grasp the amount of exercise and exercise intensity, including mild shortness of breath, feel a little heartbeat, slightly hot around the body, slightly red face, Jinjin small sweat, which indicates the right amount of exercise; if there is obvious panic, shortness of breath, heart fever, dizziness, sweating, exhaustion, indicating that the exercise is over the limit. If your exercise is always maintained in the “face does not change the heart does not jump” degree, the heart rate is too far from the “target heart rate”, it means that your exercise is unlikely to achieve the purpose of enhancing physical fitness and endurance, you need to add some more. 4, duration of general health should not be less than 20 minutes per aerobic exercise time, can be as long as 1 to 2 hours, mainly according to personal physical condition. Aerobic exercise can be performed 3 to 5 times a week, the number of times is too little to achieve the purpose of exercise. 5, the post-exercise symptoms, that is, the discomfort after the exercise, is also a measure of whether the amount of exercise is appropriate scale. Generally after exercise, there can be mild discomfort, fatigue, muscle pain and other feelings, will soon disappear after rest, which is normal. If the symptoms are obvious, feeling exhausted, muscle pain, and a day or two can not disappear, this indicates that the intermediate metabolites in the cells and blood circulation accumulate too much. This is the consequence of anaerobic exercise, your next exercise can be to reduce the amount. 6, step by step this is the basic principle of all sports exercise. Exercise intensity should be gradually transition from low to medium intensity; duration should be gradually lengthened; the number of exercises increased by less. All of these should be in the range of personal adaptation slowly incremental, do not rush to achieve. Older and frailer people or people with chronic illnesses, it is more important to master the scale of exercise. It is best to go to the doctor before the exercise, a comprehensive physical examination, by the doctor according to personal circumstances, a specific aerobic exercise prescription, and then exercise according to the prescription.