Because there is no exercise for a long time, once you encounter high-intensity exercise, your muscles will secrete lactic acid (secretion of anaerobic respiration).

Lactic acid is an intermediate product produced in the process of glucose metabolism during exercise. Because the exercise is relatively excessive and exceeds the intensity of anaerobic exercise, lactic acid produced in the body cannot be further decomposed into water and carbon dioxide in a short time, and anaerobic metabolism is formed due to insufficient oxygen supply, which leads to the accumulation of a large amount of excess lactic acid in the body. Lactic acid accumulation can cause local muscle soreness. Lactic acid accumulation usually occurs. If you want to accelerate the excretion of lactic acid, one is continuous aerobic exercise to accelerate the excretion of lactic acid with energy metabolism, and the other is fumigation with hot water (such as sauna) to accelerate the excretion of lactic acid.