My father who died two years ago with the "A" at the age of 78 was a specimen of perfect physical health and had more energy than a much younger man. He lived a very long time with "A" and would have lived longer because of his physical well-being but there comes a time when the brain doesn't tell the throat to swallow and even saliva gets aspirated into the lungs. He withstood several bouts of pneumonia due to this. He was never a couch potato a single day of his life.
Most of the victims of the terrible A that we have known have been like your Father and my Mother in Law, the opposites of Couch Potatoes.