Lifespan: Why We Age—and Why We Don't Have To

And thus, the Harvard Study of Adult Development was born. The original cohort of 268 men included people from many walks of life, including some who went on to become well-known, such as John F. Kennedy and Washington Post editor Ben Bradlee. Still, over the decades it was deemed too demographically insular—all Harvard men!—to give generalizable r

There is chronic stress—the kind that comes from a bad job, sour relationship, prolonged financial hardship, or even what my friend fitness author and mega-athlete Mark Sisson calls “chronic cardio” (discussed momentarily). This kind of stress accelerates entropy and decay. It leads to prolonged elevation of the hormone cortisol, which can rob our

Hormesis, one of my favorite biological principles, is the mechanism by which small doses of stress from, say, a tough workout, a good sweat in the sauna, or even temporary calorie restriction (which we call intermittent fasting) can promote more efficient cells and greater long-term health.

In organisms, we know what causes senescence (the tendency to grow feeble with age). It is antagonistic pleiotropy, the propensity of selection to favor heritable traits that provide early life benefits even when they carry inevitable late life costs.3 This willingness to accept harm in old age occurs because selection sees the early life benefits