It's been 5 years since my AVR. I'm 69 now. I wouldn't say that I have full blown Chronic Fatigue Syndrome, but I definitely have a limitation to my stamina and fitness. I was hoping my surgery would be a ticket to renewed fitness vitality, but even though my heart is fine, my body was totally wiped out post-op. I'm a disciplined exerciser, and approach it with tiny increased increments. I seem to have plateaued at very slow walking for an hour, (actual walking for 30 min and sort of milling around for 30 min), then I'm pretty fatigued for most of the rest of the day. I do resistance training on every muscle group (one minute per muscle per day). It's a tough irony to endure, because my lifestyle is less vital now than it was 6 or 7 years ago. The literature documents that CFS can be triggered by surgery.