Wanting to improve your health and keeping your body in good shape are absolutely terrific reasons for starting or restarting an exercise program. We know at least one third of our health problems is directly related to our body mass index. This is a measurement of our excess body fat content adjusted for individual's height. It is a good and reliable measurement and widely used in medicine and public health
decision making. In any case, your concern is finding an appropriate exercise regiment for your body with the goals of staying healthy, good shape, and not harming your muscles. This is actually a very individualized answer, and the short answer is that you have to see a sport trainer or a primary care doctor
who can assess your risks before making their recommendations. Assuming you have no joint or muscular disease, heart or lungs disease, then the best form of exercise is probably aerobic exercise. Aerobic exercise can range any where from walking, running, swimming, soccer, basketball, or baseball. You need to be able to sustain at about 60% of your maximum cardiac function for about 30 minutes, 3 times a week. However, you need to select the type and duration as well as frequency of your exercise program that will work for you. The more you are able to do with some exceptions, the better it is. Your muscles will get micro tears all the time with exercise, but they can heal without any problems. Please see a primary care physician for a consultation.