The gym is on of the few places that everyone, regardless of size, condition or age can all exercise together.You may be a conditioned athlete, or a professional couch potato, but you can start on a safe and successful fitness program at any time in you life.
Strong muscle will increase your metabolism, strengthen your bones and support your joints. It will also make you look and feel better. Combine weight training with cardiovascular work and you will have a healthy body and feel great.
Starting out with a full body program, means you are working all your muscle groups in one day, and how many reps and sets depends on your current fitness level.
The next step means working into a split program, where you do one body part each day. The benefits are you work that muscle group harder and give it more time to rest.
Another option is hybrid training, combining functional training with aerobic work to increase the metabolism.
The truth is anything works, it's all about moving and pushing yourself a little.