Evolution Explains Why Exercise is Essential, Especially as We Age.

High levels of physical activity may become even more important for health as one gets older, as suggested by a new paper on something biologists call the “active grandparent hypothesis."

In his recent book “Exercised”, the well-known evolutionary biologist Daniel Lieberman coins a term — exercists— which he broadly defines as people who espouse the benefits, joys, and importance of regular exercise, sometimes to a fault. And we all know those people (or perhaps are those people, not to turn the mirror on myself). While generally well-in…