One way that helps keep your body healthy is to exercise. There are a number of options for fitness that can be social and fun. Walking is good for those who can use their legs. It requires little equipment (good shoes), is free, and reduces stress. Swimming provides a full body workout with little physical stress and is relaxing as well. Consider other activities such as dance, aerobics, group sports, or using exercise bicycles.
Whatever you decide to do, be sure the activity is medically appropriate that it is conducted safely with low risk of injury or harm.