The Benefits of Middle-Age Fitness

Americans are living longer, with our average life expectancy now surpassing 78 years, up from less than 74 years in 1980. But we are not necessarily living better. The incidence of a variety of chronic diseases, like diabetes, cancer and heart disease, has also been growing dramatically, particularly among people who are not yet elderly.

The convergence of those two developments has led to what some researchers have identified as a “lengthening of morbidity.” That means we are spending more years living with chronic disease and ill health — not the outcome that most of us would hope for from a prolonged life span.

But a notable new study published last week in Archives of Internal Medicine suggests that a little advance planning could change that prospect. Being or becoming fit in middle age, the study found, even if you haven’t previously bothered with exercise, appears to reshape the landscape of aging...