Another reason why exercise is good for healthy longevity is noted at EurekAlert!: "Exercise increased the growth of new muscle cells and blood vessels in the weakened muscles of people with heart failure ... researchers investigated whether exercise training could activate progenitor cells, a pool of immature cells in skeletal muscle that can divide into various mature cells as needed for muscle repair. Compared with healthy people, those with heart failure have about a 50 percent reduction in the number of progenitor cells in their muscles ... With exercise, the number of progenitor cells became almost normal, the cells started to divide again, and they began to differentiate into myocytes (muscle cells). And that's exactly what patients with heart failure need - replacement of muscle cells." The same mechanisms are at work in the rest of us as well. While we await the advent of medical technologies capable of reversing age-related degeneration, it makes sense to take good care of our long term health and longevity. Why reduce your chances of living into the age of rejuvenation medicine when there is so much you can do to move the odds?