I have been going to the YMCA since I retired 11 years ago. Once I turned 65  with Silver Sneakers and Silver and Fit I also go to LA fitness, and any other gym that is part of the program. These are all free as part of the Medicare Advantage Programs. This works out good especially if you travel or go south for the winter. I am much stronger now than when I was in the military 50 years ago so yes exercise does work. I don't have any diet that I follow and am pretty omnivorous, I could eat a lot better than I do. I have arthritis in my knees and a torn meniscus in my left knee, so I don't run anymore but still ride a bike.