In most cases, you suddenly want to exercise because you see others exercising, and the effect is particularly good. At this time, you want to get close to these excellent people, and you also think that if you become particularly excellent, there must be many people pursuing you, or you will have more opportunities. Besides that, you have more free time at this time and won't be particularly busy. You won't have anything to worry about, so you have the conditions to do it, so you suddenly want to exercise. Some people have the same idea after watching Tik Tok.