When exercising, the body's metabolism is accelerated, the body lacks oxygen, the main path of sugar metabolism from the normal aerobic metabolism to the anaerobic metabolism (i.e., glycolysis) pathway that can quickly supply energy. Aerobic metabolism produces carbon dioxide and water, while the end product of glycolysis is lactic acid.
If the exercise is too strenuous or prolonged, or if the body does not have enough of the vitamins and minerals necessary to break down the lactic acid, then the lactic acid in the body is not processed in time, resulting in a buildup of lactic acid. Excess lactic acid will make the weakly alkaline body fluids acidic, affecting the smooth absorption of nutrients and oxygen into the cells and weakening their normal function. Muscles that accumulate lactic acid will contract, which squeezes blood vessels and makes blood flow poor, resulting in muscle aches, chills, headaches, and a feeling of heaviness in the head.
The only way to solve this problem is to exercise more to promote the consumption of lactic acid in the body and prevent the buildup. And it is recommended to start doing fast walking, jogging and other aerobic exercise, the amount of exercise should also be controlled, to be gradually adapted to the body to increase the intensity and volume of exercise, gradually, the feeling of back pain after gym class will disappear.