Simple practices that people tend to ignore play a big role to keep people fit. Practices like walking to the market, riding a bicycle and doing household chores may help to shape up the body especially to those beyond age 40. Why should you board a car to the market yet you have the time to walk?
You do tend to start losing more muscle mass after 40 and its harder to break down protein as the body ages-protein is good for repairing the muscles. You could choose walking because its a low impact kind of exercise and does not wear your joints out so much either. They do have some good youtube workouts that are very simple-and they have some good scenery in these videos to motivate you at home to workout as well-like the one below.