More Exercise is Better

Dr. Paul Williams of the University of California at Berkeley thinks that the American Heart Association's recommendation of "half an hour a day of exercise" is way too little. He has followed more than 100,000 runners for 20 years and has shown that exercising much more than that will dramatically reduce the high incidence of heart attacks, strokes, certain cancers, glaucoma, diabetes, cataracts, macular degeneration, gout, gall stones, diverticulitis, and many other ailments (Medicine & Science in Sports & Exercise, March 2009). Dr. Williams found that running 40 miles per week can lower risk of stroke by 69 percent, heart attacks by 37 percent and diabetes by 68 percent. To prevent progressive weight gain with aging, the runners needed to add 1.4 miles a week each year.

How inactivity kills: Human muscles get their energy by extracting sugar and fat from their blood supply. When muscles are at rest, they need insulin for sugar to pass into their cells. However, when muscles contract, sugar passes into their cells without requiring insulin.

Extra fat blocks insulin receptors so insulin can't do its job of driving sugar into cells and blood sugar rises to high levels. This causes sugar to stick to the surface of cell membranes. Once stuck to cell membranes, sugar can never get off and is eventually converted to sorbitol which destroys the cell to cause all the terrible side effects of diabetes.

The extra sugar outside cells is converted to fat, which blocks insulin receptors even more and prevents insulin from doing its job, leading to more weight gain and eventually to diabetes. Thirty-five percent of North Americans will become diabetic because they exercise too little and eat too much. More on why inactivity shortens life Why more exercise is better: Contracting muscles remove sugar rapidly from the bloodstream, without needing insulin, during and for up to one hour after exercise. The effect tapers off to zero at about 17 hours (American Journal of Clinical Nurtrition, July 2008). You are protected maximally from high rises in blood sugar and fat during and immediately after exercise. Therefore, the more time you spend contracting muscles, the longer you will be protected from the cell damage that leads to cancers, heart attacks, strokes, and other consequences that shorten your life or impair its quality.