Note that the biggest reduction in mortality was found in people who walked for an hour a day. Yet that group probably contained the most of what you call "subc

Note that the biggest reduction in mortality was found in people who walked for an hour a day. Yet that group probably contained the most of what you call "subclinically ill". After all that's one of the easiest forms of exercise and there is a higher likelihood it will be chosen by people with health problems, diagnosed or not.