Then, why not do strenuous exercise after dinner? Before talking about this problem, we must first understand how food is digested and absorbed in the human body.
Food enters the mouth, and after chewing and grinding, starch is preliminarily digested by saliva. Then it enters the stomach through esophagus, where protein is preliminarily digested by gastric juice. Later, food enters the small intestine again. Small intestine is the most important place for digestion and absorption. The food processed by the mouth and stomach is completely digested by the small intestinal juice secreted by the small intestinal glands, the pancreatic juice of the pancreas and the bile of the liver, and becomes a nutrient that can be absorbed by the human body. These nutrients are mainly absorbed in the small intestine. It is transported to all parts of the body through blood and supplied to tissues and cells.
It should be understood that the secretion of digestive juice and the movement of digestive organs are closely related to the blood supply of digestive organs. There is more blood in the digestive organs, and more digestive juice is secreted, so the digestive organs are active in exercise and digest and absorb well. Because the raw materials of digestive juice are supplied by blood, so are the energy-supplying substances and oxygen needed for digestive exercise, and the absorption of digestive substances also depends on blood. On the contrary, the digestive organs have less blood, less secretion of digestive juice, inactive digestive movement and poor digestion and absorption ability.
However, when you do strenuous exercise after a meal, the blood that should flow to the digestive organs will be first dispersed to the muscles of the whole body due to exercise. When there is more blood in muscles, there will be less blood in digestive organs, and less blood in gastrointestinal tissues will bring difficulties to digestion and absorption. Physiologists tell us that during strenuous exercise, sympathetic nerves are extremely excited, while parasympathetic nerves are inhibited. The secretion of digestive juice is mainly caused by parasympathetic nerve excitation, and digestion is also strengthened by parasympathetic nerve excitation. When sympathetic god is excited, digestion is inhibited and the blood vessels of digestive organs become narrow. Moreover, after eating, I take part in strenuous exercise. Because my stomach is full of food, I feel very shaken during exercise and often have abdominal pain. Swimming after meals is even worse, because the low water temperature takes away a lot of heat from the human body, and the activities of digestive organs such as the stomach and intestines are inhibited, which affects the digestive ability; When the human body is in water, it will also be under the pressure of water. Water oppresses the gastrointestinal tract full of food, which is not only bad for digestion, but also prone to abdominal pain.