Oscar Wilde, in The Picture of Dorian Gray, describes a young man who remains unchanged at the epitome of youth, while a painting of him, locked away, is gradually transfigured by the ravages of age and sin.
painting of him, locked away, is gradually transfigured by the ravages of age and sin.After witnessing 18 years of Dorian Gray’s unaltered beauty, a close friend, Lord Henry, states "I wish you could tell me your secret. To get back my youth I would do anything in the world, except take exercise, get up early, or be respectable. Youth! There is nothing like it." While Lord Henry’s aversion to fitness is still professed by some, exercise itself has become the modern fountain of youth.
Some runners seem to defy aging. Octogenarians complete marathons and masters runners achieve world class finishing times. All runners experience the exhilaration of exertion and are instilled with youthful vigor, strength and stamina. This raises a profound and fascinating question: does running, in and of itself, extend life expectancy?
Many studies address this question, but most do so indirectly. A great deal of research demonstrates that exercise decreases the risk of specific diseases. We now have definitive evidence that exercise reduces the risk of heart disease, strokes, some types of cancer, and many other diseases. One is tempted to infer that if running decreases the risk of the most common causes of death, then running must improve life expectancy. While this logic is compelling, it does not meet the rigorous standards required for medical proof.
For example, what if fatal cardiac arrhythmias induced by running outweighed the beneficial effects on the heart? Might running increase the production of free radicals, highly reactive byproducts of energy production, thereby accelerating aging and the pathogenesis of disease. Could the hormonal changes in female athletes predispose them to premature mortality? The countless effects of running, both salubrious and deleterious, cannot be added together in a simple sum to predict an overall effect on life expectancy. Greater insight into the effects of exercise on longevity can be gained through the empirical results of clinical trials.
Longitudinal Looks at Longevity
A landmark study relating exercise to mortality was published in the New England Journal of Medicine in 1986. Dr. Ralph Paffenbarger and his colleagues collected data on 16,000 men, all graduates of Harvard, including college physical exams, participation in intercollegiate athletics, and a series of surveys starting in the 1960’s regarding levels of physical activity and participation in sports. Mortality statistics were collected with the aid of the Harvard Alumni Office.