I'm curious as well. I have ascending graft with ON-X AVR. My surgeon discouraged even (modified) pushups. I thought it might have been fatigue life of the graft. No- He explained that graft is relatively stiff while the remaining aorta is compliant, and the connection between the two are these sutures - that is where stress concentrations occur. ~60 bpm over 3 decades is a billion cycles!I'm not advocating for anything here, just pondering what is possible for people post-surgery and how varied the medical advice is.