The key to beating dementia

Like every other part of your body, the brain needs a steady supply of blood and oxygen -- and exercise is one of the best ways to give it plenty of both.

Now, a new study shows of the benefits of exercise how all that blood-pumping exercise can lead to some very real physical benefits inside the brain itself -- including a slower rate of brain shrink.

The study of more than 600 people tracked for three years starting at the age of 70 found that the ones who got the highest levels of activity had the slowest rate of that shrink.

Now, all our brains lose a little something as we get older, so you can expect even a normal brain to shrink at least a little bit over the years. But the more you lose, the more likely you'll find yourself battling dementia -- and that's why slowing that shrink is absolutely critical.

And along with brains that shrink less, the seniors who got the most movement and the most benefits of exercise also had less damage in the white matter of the brain. Think of that white matter as the wiring that keeps the communication lines in the brain open. When the lines go down, you've got problems.

It doesn't take much to get the benefits of exercise. The seniors who got the most movement in the new study weren't exactly training for the Iron Man competition. In many cases, they were simply walking more.

One more note: The study didn't find any benefit at all for mental and social stimulation. But I've seen plenty of other research that has -- so along with a brisk walk, give your mind a workout.

Anything from a crossword puzzle to bingo night could help. Walk to your bingo night, and you could kill two birds with one stone.