The Key to a Strong Immune System

I'm not a couch potato, but I've not been a great one for exercise either.  I've kind of gone at it in fits and starts throughoutt my life.  I know I need it to be healthy, but I never knew what to do.  I've tried going to the gym, but by the time I drive there and have a 1 hours class and drive home, 2 hours of the precious time I have in my day have been used up.  Maybe you can relate.  I also got "post-exercise fatigue" when I had untreated hypothyroidism.  I don't have that anymore, so now I have no excuse.

What's haunted me though is what I read Dr. Michael Colgan say in his book The New Nutrition: Medicine for the Millenium:  "If you don't have time to exercise, you'd better reserve a lot of time for disease!"