It's a new indication that physical activity early in life is important for brain function later in life. Canadian researchers think they've found a connection between exercise as an adolescent and fewer cases of senility in senior women.
This doesn't prove that exercise always lowers the risk of dementia. But it does support the theory that the sooner one starts exercising, the better.
It's not yet clear whether men may benefit in the same way.
The study appears in today's issue of the "Journal Of The American Geriatrics Society."