Keep Your Brain Young

They teach neurology — he's at Johns Hopkins, and she's at Harvard. Together, these cerebral types have written a fitness book to keep your gray matter in the pink.

Preserving your smarts, they argue, depends on a positive attitude and physical and mental exertion. Activities like swimming can prod the brain to produce the chemicals it needs to function in old age. Mental aerobics like crossword puzzles may strengthen connections between nerve cells and possibly aid in forming new neurons.

The authors believe that women may live longer than men because they shop, a pastime that requires both physical (walking and carrying bags) and mental (price-comparison) skills. There are no radical new theories here — just sharp insights into what goes on up there and how to keep your brain whole as you grow older.