Many foreign scholars have revealed that the state of human ability changes overnight. 8: 00-12: 00 and 14: 00-17: 00 every day are the times when the speed, strength and endurance of chickens are in the best state. If you do physical exercise and sports training during this time, the effect will be better. But from 3: 00 to 5: 00, 12 to 14, it is in a relatively low state. If you are engaged in sports during this time, you are easy to get tired, and when the "load" is too large, the probability of sports injury is high. This shows that people should choose the best time to engage in sports activities according to the possibility of objective conditions in order to receive good fitness and training results. As far as health is concerned, it is effective to start exercising at any age. Exercise more when you have time, but exercise less when you have no time. Just move, even if it's just a trick. When is exercise good? This is a controversial issue. It is said that plants breathe out a lot of carbon dioxide after a night of metabolism, so the concentration of carbon dioxide in the Woods is relatively high in the morning, and some dust is floating in the air, which is not good for people's health. In addition, people's blood pressure is relatively high in the morning, which is prone to problems. In fact, whether to exercise in the morning depends mainly on the purpose of exercise. If it's to lose weight and increase the memory of motor skills, morning is good. When people wake up in the morning, they have consumed almost all the energy they ate last night. At this time, not eating and not exercising will lead to a result-"burning" fat. There is still some glycogen in the liver because there is no energy in the morning. When the concentration of these glycogen is reduced to a certain extent, fat "burning" will become the dominant way of energy supply, thus making it possible to lose weight. Therefore, exercise in the morning has special benefits for losing weight and preventing fatty liver. Besides, it is easier for people to learn aerobics, ballroom dancing and Tai Ji Chuan in the morning than at other times. Therefore, the health benefits of morning exercises are more in a sense. The ancients paid attention to "smelling chickens and dancing", and fitness was generally chosen in the morning. As for the carbon dioxide in the air in the morning, the serious pollution is not the main reason. In fact, the pollution of automobile exhaust during the day is also very serious, which will release lead, heavy metals and some chemical wastes, such as benzene. Blood pressure is high in the morning and can be adjusted by drugs. Therefore, when is the best time to exercise is not absolute. It also varies from person to person. Whether in the morning or afternoon, you should exercise moderately. As far as health is concerned, it is effective to start exercising at any age. Exercise more when you have time, but exercise less when you have no time. Just move, even if it's just a trick. Exercise should vary from person to person and step by step. Don't be too intense at first, and then gradually increase the amount of exercise, not just simple activities, to solve problems. In addition to heart rate, there is also the simplest way to measure whether exercise is excessive. If you can't breathe during exercise, it means that you exercise too much.