I don't know the detailed "mechanism" and reason, but I think it should be that during exercise, the increase of blood circulation makes the body get more oxygen supply than when it is quiet, and the supply of other nutrients in the blood accelerates metabolism.
In addition, when you do a lot of exercise, your body's muscle tissue is always in a state of tension. Once you stop exercising and have a short rest or recovery, your whole body muscles are relaxed in a quiet state, so you will have a sense of relaxation.
Related instructions
After strenuous exercise, in order to keep the body temperature constant, blood vessels on the skin surface expand, sweat pores expand and sweat increases, which is beneficial to heat dissipation. At this time, if you take a cold bath, the blood vessels will contract immediately due to sudden stimulation, the blood circulation resistance will increase, the burden on the heart and lungs will increase, and the body's resistance will decrease, so people will easily get sick.
If you take a hot bath, the blood flow to the skin will continue to increase, and too much blood will flow into the muscles and skin, resulting in insufficient blood supply to the heart and brain, dizziness in the light, collapse and shock in the heavy, and other chronic diseases will be easily induced. So after strenuous exercise, you must have a rest before taking a bath.
When thirsty after strenuous exercise, some people binge drink boiled water or other drinks, which will increase the burden of gastrointestinal tract and dilute gastric juice, which not only reduces the bactericidal effect of gastric juice, but also hinders the digestion of food. Drinking water too fast will also make the blood volume increase too fast, which will suddenly increase the burden on the heart, cause temporary disorder of electrolytes such as potassium and sodium in the body, and even cause heart failure, heart tightness and abdominal distension. So don't drink too much water after exercise, let alone cold drinks, otherwise it will affect your body temperature and cause colds, abdominal pain or other diseases.
Baidu Encyclopedia-Sports (sports terminology)