The new year always brings thoughts of change. Most people who make resolutions do not keep them - mainly because it is just so hard for humans to change. There are physiological reasons behind the difficulty of change - mainly relating to dopamine. In order to get yourself to stick with a change, you are really re-wiring your brain.
If you decide that working out is going to become a new activity for you in 2007, you will need to make some changes. First, set a reasonable goal. This could be to start working out 1 more day per week than you were before. (So, if you were not working out at all, start with one day per week). When you succeed, give yourself a reward - immediately. After you have worked out one day per week for two consecutive weeks, give yourself another, bigger, reward and add another day. Your rewards can be small, but continuing to deliver new rewards for your new behavior will replace the old rewards for the old behavior and will help you make your change positive and permanent.
Another factor that effects successful change is stress management. The more stressed you are, the harder it is to change. (I didn't need to tell you that....) What's interesting is that our body physically WANTS the bad habits that are our auto-pilot comfort zone when it's stressed.
Another reason why it's hard to change is because as adults, we are essentially hard wired. Our neurons have travelled the same paths a million times. To make them take new routes is terribly difficult and requires a great deal of energy and attention.
You have to eliminate the old pathways in order to develop new ones. That can mean going to a totally different grocery store when shopping for food, just so you don't fall into your old patterns. It's also easier to make a healthy change when you find an old pattern that you have abandoned that you can re-awaken. In terms of exercise: what was the one exercise you really liked at one time in your life? Even if it was roller skating...starting that again, will be much easier than starting something new from scratch.
Change. It's really hard. You are literally re-wiring your brain. It's also possible, and the rewards can be great. Think about change like you think about learning a new instrument. It's not easy, it takes lots of practice, and most of us need lessons.