"As little as four hours a week was as beneficial as more vigorous or prolonged activity. "
It's never to late to start, either. Just walk in short intervals several times a day and you 'll increase your chances of seeing your granddaughter on her wedding day (and maybe you'll be first on the dance floor!).
A side benefit to all this--less depression, loneliness and a greater ability to perform daily tasks.
So get moving.
For more on walking to maintain your health, visit 50somethinginfo.com.