Personal fitness is the art of developing a body which can perform certain tasks, most obviously the tasks involved in day to day living. It is important right from the start to realize that fitness is not the same as health. The two can co-exist quite easily, and often do, but they are definitely not the same. It is possible to be extremely fit while at the same time being fundamentally unhealthy. The key to achieving health with fitness is to train in the right way, so that fat is being burned and not muscle or oxygen.
The key to achieving this is to exercise within certain limits. The best tool you can possibly buy at the start of an exercise program is a heart rate monitor, as this will demonstrate to you whether you are exercising in a way which will build health, or a way that will diminish it. There is a formula, which is calculated using your age and heart rate, which will tell you whether you are exercising in the right way. If you are close to going over into unsafe territory, you can throttle back and recover.
If your goal is to develop balanced overall fitness, you will need to start by building up your aerobic base. As you continue to exercise within that safe parameter, your body will develop a greater aerobic capacity. This means that you will be able to carry out a greater amount of anaerobic strength fitness without it becoming dangerous. As your aerobic fitness levels increase, so you can bring in other exercises which are designed to strengthen muscle, or exercises which look to develop one part of the body which is weak.Read more about muscle strengthening exercises http://www.realsimple.com/health/fitness-exercise/workouts/exercises-muscle-maintenance-10000001700850/
As you progress with a balanced program, you develop both your health and your fitness together, achieving a far more beneficial state of being. From this solid base, you can then go on to safely explore other aspects of fitness, including disciplines such as weight training which place enormous stress on parts of the body. If you make sure you are training safely, and not putting too much strain on any one individual muscle group, you will drastically reduce your chances of sustaining an injury.
You can achieve a high level of personal fitness in your own home, or you can join a professional gym. Either approach has its merits, and there is no one solution which is right for everyone. Either will involve an outlay of money. Gym memberships are not cheap, so make sure you are getting good value for them if you choose to go that way. The alternative of equipping your own gym at home can vary enormously in expense, depending on the type of equipment you want to use. Working at home gives you maximum freedom and guaranteed schedules, while a gym has trainers who can help with your personal fitness.