Why To Exercise Today: Youth And Shiny Fur

At a month shy of 75, she has no chronic illnesses, takes no medications regularly and exercises consistently. Sure, her aggressive tennis game has mellowed, and she's not the driven athlete she was back in early 70s, when, as a single mom, she awoke at dawn, drove to a park in Red Hook, Brooklyn and jogged around a track with a group of women wearing Keds and tight Danskin shirts in lieu of running bras.

But she showed me early on how vigorous exercise throughout life can thwart depression and preserve at least a bit of youth as time marches uncontrollably forward.

So it gave me a lift dwelling on this morning's "most viewed" story in The New York Times: Gretchen Reynolds on how exercise can actually alter the course of aging (ok, it's in mice, but still...)

In addition to keeping a strain of mice from becoming prematurely gray, Reynolds reports that "exercise reduced or eliminated almost every detrimental effect of aging in mice that had been genetically programmed to grow old at an accelerated pace."

At 8 months, when their sedentary lab mates were bald, frail and dying, the running rats remained youthful. They had full pelts of dark fur, no salt-and-pepper shadings. They also had maintained almost all of their muscle mass and brain volume. Their gonads were normal, as were their hearts. They could balance on narrow rods, the showoffs.

But perhaps most remarkable, although they still harbored the mutation that should have affected mitochondrial repair, they had more mitochondria over all and far fewer with mutations than the sedentary mice had. At 1 year, none of the exercising mice had died of natural causes. (Some were sacrificed to compare their cellular health to that of the unexercised mice, all of whom were, by that age, dead.)