Is it better to do aerobic exercise on an empty stomach or after a meal?

There is no absolute "optimal solution". Choosing whether to do it on an empty stomach or after a meal depends entirely on your physical condition, exercise goals and daily habits. It is easy to cause problems if you just copy other people's experience.

Speaking of which, the first time I came into contact with fasted aerobics was through an old friend in the fitness circle who was preparing for a competition. At that time, he applied fat before the game, set an alarm for six o'clock every day, got up, took an electrolyte tablet, and went to the gym to ride a spinning bike for 40 minutes. He didn't eat any meals. In three weeks, his body fat dropped from 18% to 12%, and his abdominal muscles were as clear as if they were carved out. There is actually a solid physiological basis behind this: after a night's rest, only 30%-40% of the liver's glycogen reserve remains in the fasting state. At this time, if you do low-intensity aerobics, the proportion of fat energy supply will be 20%-30% higher than after a meal. The fat-brushing efficiency is really high. This is why fitness parties have been pursuing fasting aerobics for so many years.

But I fell into a trap the first time I followed it. At that time, I had just been exercising for half a year. I didn’t have much muscle mass and I didn’t have a history of hypoglycemia. I woke up on weekends and climbed the stairs on an empty stomach. Only the voice-activated lights in the corridor lit up as I walked. When I climbed to the 15th floor, my vision suddenly went dark and my ears were buzzing with my heartbeat. I held on to the handrail for a long time before I could walk down. I felt a little dizzy for two days in a row. Later, I learned that the threshold for fasted aerobics is not as low as everyone thought: there are no hypoglycemia problems, the body fat rate is relatively high, the exercise intensity is controlled at 60%-70% of the maximum heart rate (that is, the level where you can talk a little breathlessly but can still communicate normally), and the duration does not exceed 45 minutes. It is cost-effective to do fasted aerobics if these conditions are met. Otherwise, you may feel dizzy and nauseated, or you may actually suffer from hypoglycemia and syncope, which is not worth the gain.

On the other hand, if you have underlying health problems or don’t like to exercise on an empty stomach, there is really no need to follow the fasting trend. My mother has type 2 diabetes, and the doctor has repeatedly warned her not to move on an empty stomach. Her current habit is to clean up the dishes after dinner, take a 40-minute rest, then carry her small stereo and go to the community square to dance with the old sisters for half an hour. When she comes back, her blood sugar test is more stable than before the meal. The doctor praises her for her good habit. For ordinary fitness enthusiasts, if you do aerobics 1-2 hours after meals, your glycogen will be sufficient, your exercise performance will be much better, you will not be tired easily, and you can avoid excessive muscle decomposition. Especially those who are in the muscle-building period. If you want to add aerobics after strength training, you must have something to rest on before practicing, otherwise you will not be able to lift the barbell, let alone the subsequent aerobic consumption.

Oh, by the way, several misunderstandings that have been making a lot of noise on the Internet can also be explained clearly: Many people are afraid of losing muscles during fasting aerobics. In fact, there is really no need to worry too much. As long as you meet the conditions mentioned above, the amount of muscle decomposition is very small, and you can replenish it by eating enough protein later.； It is also said that exercising after a meal can cause gastroptosis. This is a problem that can occur only if you do high-intensity strenuous exercise immediately after eating for a long time. For ordinary people, take enough time to rest after eating, take a walk and do some exercise. That amount of exercise is not enough to hurt your stomach, so there is no need to scare yourself.

Now I don’t worry about it at all: I got up early on weekends and didn’t eat too much the night before, so I took my keys and walked to a park near my home for 40 minutes, listening to music in the morning breeze, and then came back to eat freshly steamed meat buns from the breakfast restaurant, feeling refreshed.； If you go to the gym after get off work on workdays, you can first eat a banana or a piece of whole wheat bread at the company to cushion your stomach. After doing strength training, you can then ride the elliptical machine for 20 minutes. You will not feel dizzy and your condition will be just right.

Really, there are not so many black and white standard answers to exercise. If you try it on an empty stomach once and it doesn’t feel uncomfortable, and the fat loss efficiency is in line with your expectations, then keep doing it.； If you feel hungry and panic once, don't hold on. There's no shame in practicing after meals. It's better than waiting for the so-called "best time" and just lying down in the end, right? Long-term persistence is the most important thing. As for whether you are fasting or after eating, your own comfort is the most important.