What to do:  Do regular, vigorous aerobic exercise. You should ideally work up to a high pulse rate, out of breath and covered with sweat.  Studies have shown the importance of intensity of exercise so try to get up to a vigorous level of exercise.  Thirty minutes a day at least 3 to 5 times per week is reasonable for aerobic exercise.   Please see your physician before beginning any exercise program as there are contraindications to exercise.  Go slow at first as it takes months for profound changes to occur in your body.  Be careful to avoid injury.  Hire an expert trainer as desired. 

    Weight-lifting or resistance exercise should also be added, usually two or three days a week with a non-weight-lifting day in between.  Weight-lifting raises the level of growth hormone, strengthens muscles and joints and reduces osteoporosis, and protects against free radicals.  Start slow with one set and lighter weights and work up to 3 sets of about 12 repetitions each.  The weights should be heavy enough that you exhaust the muscle in about a dozen repetitions for each set.  Do the major muscles groups of the body.  Weight-lifting is associated in men with a 40% reduction in cancer.  Many studies have shown the health benefits and increased longevity associated with exercise, here are a couple:

Basic Science: the Stanford and Harvard Studies

    The Stanford/VA Palo Alto study measured the maximum or peak exercise capacity of 6200 men and compared that measure to mortality over 10 years.   The men ran on a treadmill that increased speed and angle until they could no longer run or had chest pains.  Their maximum effort was measured in METS; one MET is the amount of oxygen the average person uses while sitting down.  Five MET equals walking at 4 mph and 8 MET jogging at 6 mph.  The scientists found that for every MET increase in a man's exercise capacity, the risk of mortality dropped by 12 percent.  Those with a maximum capacity of less then 5 MET had double the chance of dying from any cause compared to men with an exercise capacity of 8 MET or more.  In this study exercise capacity was a strong predictor of the risk of death, and was a better predictor of mortality risk than high blood pressure, diabetes, or even how much you smoke. 

    The Harvard Alumni Health study examined 17,321 Harvard alumni for all cause mortality in relation to vigorous (> or = 6 MET) or non-vigorous (< 6 MET) physical activity.  There was a graded inverse relationship between total physical activity and mortality, and vigorous but not non-vigorous activities were associated with longevity.  Another study of 11,130 Harvard alumni examined the incidence of stroke.  Light intensity activities (<4.5 METs) were unrelated to stroke risk but more vigorous activities showed decreased stroke risk as exercise increased but only up to a moderate point.  A 2001 Harvard article extolled exercise and stated physical activity adds years to your life.  The American Cancer Society recommends exercising 30 minutes per day, 5 days a week to prevent cancer.