The secret of aerobic exercise for weight loss

　　First, let us understand some necessary basic concepts and physiological knowledge, which are important prerequisites for designing an aerobic prescription for yourself.

　　one. heart rate

　　This is the most direct indicator of the effectiveness and intensity of aerobic exercise. Many fitness equipment in gyms now have calorie (calorie) consumption counters. But in fact this count is generally very different from actual consumption, and there is no constant ratio between calorie consumption and fat consumption. Fat catabolism is a complex series of biochemical reactions, and heart rate reflects sympathetic nerve The excitement of the sympathetic nerves promotes the secretion of a series of lipolytic hormones, thereby activating lipolytic enzymes and decomposing fat stored in adipocyte tissue into free fatty acids and glycerol. Fatty acids can be decomposed into carbon dioxide and water and release a large amount of energy under conditions of sufficient oxygen supply.

　　So what heart rate or intensity should be reached during exercise to effectively lose weight? It should usually be 60%-75% of the maximum heart rate (MHR/220-your age). That is to say, for example, a 30-year-old friend has a maximum heart rate of 220-30=190. Then 190×60%=114~190×75%=145, that is, the heart rate remains around 114~145 exercise It is effective and safe. Since the maximum heart rate is an estimate of the heartbeat limit based on physiological conditions, the actual intensity depends on the individual. For beginners, it can usually be maintained at 60 to 65% MHR. If you blindly pursue high intensity regardless of your physical condition, it will be detrimental to healthy。

　　2. Time

　　According to American sports medicine research, muscle glycogen is the main energy supply in the first 15 minutes of aerobic exercise, and fat energy supply only starts 15 to 20 minutes after exercise. Therefore, aerobic exercise is generally required to last for more than 30 minutes. Then a question arises. Does everyone have such basic physical fitness to exercise at a high intensity such as 65% MHR for 30 minutes or more? Let us first look at the concept of exercising at a high intensity such as 65% MHR for 30 minutes. Adult women's 800-meter and men's 1,500-meter long-distance running can generally reach the required heart rate. Most people should have such an experience in physical education classes. The time to reach the standard is 4 to 5 minutes and 6 to 7 minutes respectively. So that means running 6 to 8 kilometers at a moderate speed can achieve 65% MHR aerobic exercise for 30 minutes.

　　I believe that most non-athletic people do not have such physical fitness. If you barely insist on completing aerobic exercise of such intensity and time, it will cause physical fatigue. Many friends who have skipped aerobics may have had this experience: they went to aerobics, lost weight, but were exhausted, and were not energetic at work the next day. They gave up after a while, and then returned to their previous physical condition. Therefore, do not simply take the research results out of context as the premise for aerobic exercise prescription, because the research only measures average statistics. Whether muscle glycogen can supply energy for 15 minutes depends on each person's reserve. From the lipolysis process mentioned above, we can see that the so-called fat energy supply starts after 15 to 20 minutes of aerobic exercise. It only reflects the biochemical reaction time of lipolysis energy supply. Unlike muscle glycogen, fat can directly supply energy to the body, and this reaction time also depends on each person's physiological conditions. Therefore, the exercise time should be gradual. The duration of continuous exercise can reflect the body's endurance conditions, and the improvement of endurance cannot be achieved through one or two exercises. Of course, the exercise time is too short and cannot achieve the purpose of weight loss, because only the body consumes the energy generated by fatty acid oxidation in order to further promote the decomposition of more fat. And ultimately achieve the goal of losing weight.

　　So how to solve this contradictory problem? I suggest that friends who are not in good physical fitness but are relatively obese should use interval training when they first start aerobic training. Use a high heart rate (intensity) for a period of time until you start to feel tired and then slowly switch to some relaxation or slow-speed exercise. Maintain a faster heart rate (moderate intensity) until your physical strength has recovered and then switch to a high heart rate (high intensity). I don't agree with continuing to exercise even if you feel very tired. Although this exercises your willpower, a step-by-step approach is more beneficial to your health and will not make you exhausted after one exercise and unable to face the next day's work. If you exercise in a step-by-step manner for 45 minutes to 1 hour, the weight loss effect will not continue to be worse than exercise. Of course, interval training is a transitional training method. The ultimate goal is to enable you to easily complete 30 minutes or more of high-intensity aerobic exercise. This will not only achieve the goal of losing weight, but also greatly improve your endurance and cardiopulmonary function.

　　3. Oxygen

　　In the previous article, I mentioned that fatty acids can decompose into carbon dioxide and water and release a large amount of energy under sufficient oxygen supply. Therefore, oxygen is the key to fat loss through aerobic exercise. Sufficient oxygen intake must be ensured during exercise. However, this does not mean that deep breathing during exercise can ensure oxygen intake, because the amount of oxygen inhaled does not correspond to the amount of air inhaled. If many people do aerobics together indoors, you can imagine how much oxygen can be allocated to one person, so it is best to do aerobic exercise outdoors or in a well-ventilated room.