Hello, the 40-year-old man's fitness is mainly running. If he wants to keep fit, he can do aerobic training first, such as jogging, cycling, mountain climbing, swimming and so on. Aerobic exercise can exercise people's cardiopulmonary breathing, give people a healthy heart and make people look young.

In the process of fitness, we should also pay attention to the gradual exercise, gradually increase, so that physical strength and brain can gradually adapt to avoid being tired and painful the next day. So don't rush to practice physical strength and equipment from the beginning. It is best to practice aerobic exercise for about a week first, and then gradually contact the equipment after one week.

I hope I can help you, thank you!