If the time is too long, many people don't have that much time. For students, although health is very important, but now the competitive pressure is so great, learning is also very important. If they spend a lot of time on sports and fitness every day, then their studies will not keep up.
Therefore, it is most appropriate to spend about an hour every day doing exercises during recess or extracurricular activities. They are all very tired after the second class, so let them go out and relax at this time. It can relieve brain fatigue.
Exercise for too long will make you tired. Especially for the elderly, sometimes they have to take a rest after exercising for a while. If they exercise too long, they can't adapt at all. Moreover, most of the elderly people have some diseases, which are not suitable for exciting exercise at all, nor for exercising for too long.
One hour a day, I think it should be just the right time. For example, we get up in the morning and go out for a morning run. It takes about half an hour to run and another half an hour to exercise at night.
Sometimes we exercise, not to say how long it will take, but to have an effect. Doing effective exercise at effective time is what we want. The ultimate goal of our exercise is to have a healthy body, so it is best to exercise to a certain extent.