What are the benefits of exercise?

CCTV 10 《 The Road to Health 》 did an experiment: First, let two groups of students ride bicycles to make their blood lactic acid content more than 20. Then let one group of students relax completely and sit on the floor, while the other group does slow exercise. After a period of time, measure again. Results the blood lactic acid content of students who sit down and rest is higher than that of students who do slow exercise. Some studies have found that after a short period of low-intensity aerobic exercise, the blood oxygen level in the brain has improved, even after a period of rest, which means that exercise is really good for improving the blood oxygen supply in the brain. Exercise has the function of regulating human tension, improving physical and psychological state and restoring physical strength and energy; Exercise can improve physical health, make the tired body have a positive rest, and make people energetically engage in study and work; Exercise can stretch your body and mind, help you sleep and eliminate the pressure brought by work. Exercise can cultivate sentiment, maintain a healthy mentality, give full play to personal enthusiasm, creativity and initiative, thus improving self-confidence and values, and making personality develop healthily and harmoniously in a harmonious atmosphere; Team events and competitions in sports can cultivate people's spirit of unity, cooperation and collectivism.