Whatever sport you do, it is good for your health. Obviously if you go skydiving or bungee-jumping you also practice your lungs when you scream your lungs out, but whether it is an extreme sport or any form of sport it can only be beneficial to your overall health. It is relatively easy for an unfit person to strain muscles and a sports therapist will get you back on track. Another good idea is the taking of supplements during impact sports for example. Glucosamine is very good in rebuilding cartilage and vitamin C is good for hard training.
There will always be the right sport for anyone, regardless of weight or age, just keep in mind that water is very important and plenty of it as well. When you choose a sport you must keep in mind that you must enjoy it and not see it as a chore as that is the quickest you will give up. The benefits include good shape, weight loss and high energy levels. If it is completely impossible for an individual to participate in sport itself, the importance of spectator sport must never be underestimated as it improves social mobilization, education and communication all which are greatly of benefit to good mental health.
Sport is great enhancer for self-esteem as it will motivate self-care, and not only sporting skills are acquired, but also life skills, guidance of professionals and coaches and acceptance of friendships amongst hundreds of other positive reasons. Just never overexert yourself, follow inappropriate training methods and use protective clothing and safety equipment when necessary.