You  may not realize that one of my primary intentions of going to medical school was to help improve the overall application of exercise to the treatment model.

However, after I finished it became very clear that nutrition was even more important, and even more important than both of these was resolving the underlying emotional barriers to optimal health.

However, exercise has been a life-long passion for me, and I am delighted that I have virtually all the mobility, stamina and flexibility as I did 40 years ago. I can' t run as fast as I did when I was younger, but I am not limited from participating in any activity that I choose to.

I hope to continue this fitness level for the next 50 years. Fortunately, this is something that you can also do.

If you haven't read my comment on exercise in Tuesday's issue please do so as it provides an important perspective.

Vigorous, sustained exercise does more good, not only for kids, but adults as well. And considering all the good exercise can do -- beating diabetes and Alzheimer's for starters -- you'll want to get it right the first time. There is even compelling evidence that suggests exercise makes you smarter.

There are three important variables to consider when you exercise:

• Length of time
• Frequency
• Intensity

I encourage my patients to gradually increase the amount of time they are exercising to at least one hour. Initially the frequency is daily, but this is a treatment dose until you normalize your weight or insulin levels. Once normalized, you will only need exercise three to four times per week.

Exercise hard enough so that it is very difficult to talk to someone next to you. When you are exercising that hard, your cardiovascular system is under such a significant stress that the mere act of talking makes you unable to provide your body with enough oxygen because of the diversion of airflow.

But if you cannot carry on a conversation at all, then you have gone too far and need to decrease the intensity slightly.

Most people don't exercise at the appropriate intensity and as a result aren't able to obtain the benefits. When you use the right dose you will receive absolutely amazing results, but if you under or overdose you will either not achieve the results you seek or suffer from unnecessary side effects.

The bottom line is that one of the best investments you could ever make in your health is your commitment to a regular exercise program that you can do the rest of your life. This is because exercise is not like money. You simply cannot bank it. Even if you were a world-class athlete, in about two weeks of non-exercise you would start to experience serious deconditioning.

If you need some direction to get started, I urge you to review my beginner's exercise page that includes links to other pages and a free table you can download to keep track of your progress.