David Bernstein, MD is a highly respected physician, board certified for internal medicine and geriatrics, with 40 years of experience. His two recent books, his first book "I've got some good news, and some bad news, your old". and his second book "The power of 5; the ultimate formula for longevity and remaining youthful" explain not only how to live longer but to increase your health longevity, i.e. staying active during your longer life.
David's website: https://www.powerof5life.com/