Fitness is a state of control over your environment physically, mentally, and emotionally, in such a way that you are prepared to deal with all obstacles in your life with minimal physical injury, psychological stress, or emotional anguish.
Fitness goes beyond the walls of the gym. To fully reap the benefits of being fit, you need to live it. It cannot be an activity that you add into your life when some free-time comes along. As you can see in the diagram, your mental and emotional well-being and physical well-being are tied together. If you say that you are not motivated to physically train, then you have to break into the cycle. The only way to get into the positive feedback cycle is to train. Seems ironic, huh? But, you see the training brings about achievement, confidence, enhanced self-esteem, optimism, and happiness. Your enhanced mental and emotional state of mind will bring feelings of control, focus, enthusiasm, passion, intensity and motivation.
"Nothing great was ever achieved without enthusiasm."
-Ralph Waldo Emerson