exercise the key to staying youngish?

The researchers were surprised by the magnitude of the impact that exercise had on the animals’ aging process, Dr. Tarnopolsky said. He and his colleagues had expected to find that exercise would affect mitochondrial health in muscles, including the heart, since past research had shown a connection. They had not expected that it would affect every tissue and bodily system studied.
[Source]

Exercise seems to hold promise as a fountain of youth -- at least for genetically modified lab mice.