If you want to make exercise a part of your life, it is imperative that you do it for internal reasons. John Baucom, author of Baby Steps to Success, says, "Motivation is an internal source of energy. It's composed of inner desires, urges, energy, and instincts." You have to want to do it. Your inner desires are the most powerful and most often lead to lasting effects.
Lasting success will come from being internally motivated. Richard M. Ryan, professor of psychology at the University of Rochester, says, "To really keep an exercise program going, it needs to be something you are doing because you value the actual activity-you appreciate the exercise for the sake of exercising."
I firmly believe this; however, I need to make a point. For those of you who are trying to get started with exercise, maybe for the first time, you will need more than internal motivation because that is what you lack in the first place. The very reason you're not motivated is because you don't have internal desire to exercise. You're not going to be magically motivated to exercise just because someone tells you that it's important. This is a time where it may be beneficial to use some kind of external motivator to get you going. Let me give you some examples.