If the amount of exercise increases, the oxygen, nutrients and metabolites needed by the human body will also increase accordingly, which depends on the heart to strengthen the contraction force and contraction frequency and increase the output of the heart to transport. When doing a lot of exercise, the blood output from the heart can't meet the body's demand for oxygen, leaving the body in an anaerobic metabolism state. Anaerobic metabolic exercise does not release energy mainly by fat, but mainly by decomposing sugar stored in human body. Because in the anoxic environment, fat can not only be used, but also produce some acidic substances, such as ketone bodies, which reduce human exercise endurance. After a short period of strenuous exercise, the blood sugar level will decrease, which is an important reason for hunger. At this time, people often have a strong appetite, which is extremely unfavorable for losing weight.

In aerobic exercise, glycogen stored in the human body is first used to release energy; After 30 minutes of exercise, the energy released by glycogen began to be converted into the energy released by fat; Exercise 1 hour or so, the energy required for exercise is mainly fat. For example, aerobics, which is common to lose weight and shape, lasts only about 1 hour. In other words, when fat just begins to decompose, people stop exercising, and its weight loss effect is self-evident.

Human muscles are composed of many muscle fibers, which can be mainly divided into two categories: white muscle fibers and red muscle fibers. During exercise, if you do rapid and explosive exercise, you will get white muscle fibers with thick cross sections, so the muscle groups are easy to develop and be strong. In this way, weight loss will become more and more "rough".

In short, in order to lose weight, we should do moderate and low-intensity endurance aerobic exercise for a long time (more than 1 hour), and the heart rate is 120- 160 times per minute. For example: aerobics, jogging, long-distance swimming and so on.