Physical activity, the compression of morbidity, and the health of the elderly.

The Compression of Morbidity hypothesis envisions a potential reduction of overall morbidity, and of health care costs, now heavily concentrated in the senior years, by compression of morbidity between an increasing age of onset of disability and the age of death, increasing perhaps more slowly. For this scenario to be able to be widely achieved, largely through prevention of disease and disability, we need to identify variables which predict future ill health, modify these variables, and document the improvements in health that result. Physical activity is perhaps the most obvious of the variables which might reduce overall lifetime morbidity.