Oxygen supply, under the regulation of the central nervous system, redistributes the whole body's blood, which greatly reduces the secretion of digestive glands, thus affecting the digestion and absorption of gastrointestinal tract. The more intense and lasting the exercise, the longer it takes for the digestive organs to recover, so it is a normal physiological activity for people not to eat immediately after exercise. It is generally believed that it is more scientific to rest for at least 30 ~ 40 minutes after exercise. Similarly, you can't take part in strenuous exercise immediately after meals. If you take strenuous exercise immediately after a meal, the blood that is participating in gastrointestinal digestion will be redistributed and flow to muscles and bones, which will affect gastrointestinal digestion and absorption. Taking part in strenuous exercise immediately after meals will also cause abdominal pain and discomfort due to gastrointestinal vibration and mesentery involvement, which will affect human health. So you can exercise at least after meals 1.5 hours. Less strenuous activities after meals, such as walking and mild cultural and sports activities, are not only helpful for digestion, but also beneficial to health.