Old but Not Frail looks at those who age well — and those who do not:
The researchers published their data in the May 3 issue of The Journal of the American Medical Association, finding that being unable to walk a quarter mile within five minutes portended troubles. For each minute beyond five, the risk of dying in the next four years increased by a third, the risk of having a heart attack increased by 20 percent, and the risk of having a disability increased by half.Those who took more than six minutes for the quarter-mile walk had the same risk of dying or having a heart attack as those who could not walk the distance at all, and the effect was independent of age.