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"When you sum up the powerful effects of moderate exercise on the health of older people," Rowe and Kaplan observe, "it is hard to imagine why we aren't all out there working up a sweat." Fred Piccini is doing just that--and it's paying off. On a family vacation this summer with children and grandchildren in Georgia, he found himself running and jumping on rocks right alongside the kids. He says, laughing, "I felt so much energy that I forgot I was old."
--With reporting by Michele Aulagnon/ New York, Greg Aunapu/Miami, Roberta Grant/Los Angeles, Erik Gunn/Racine and Anne Moffett/Washington