I have been in rehab, rehabilitation and physical therapy on and off for 30 years. I also was fairly athletic in my younger years, but had retinal detachment and had to restrict my movement to gentle walking and yoga. I purchased a stationary bike from Amazon for $129 and had my neighbor set it up for me. It sat without use for three years. I do light resistance exercise exercises with suits or exercise rubber bands, or just graceful movements having had ballet when I was a kid. I walked the dog and I try to keep a decent pace or walk without him. I answer all the Mayo Clinic forum stuff for an hour while I ride the stationary bike at a gentle pace. If I get the least little pains, I double check the area where I have the pain. For example, like in my knee and it’s usually because I’m not exerting pressure through my foot. I refocus on my foot applying pressure and not through my knee. So suffice to say I self correct before I damage something. Since I don’t work at a really high cardiac or cardio rate, I have to put in more time. So 20 minutes isn’t good enough for me. The hour or hour and a half of gentle continuous exercise is good. When I had so much pain I couldn’t stand it. I started back on some exercise. First day it was five minutes second day it was 30 minutes and then I found myself up to an hour and today it was 100 minutes after four weeks And then two gentle walks morning and afternoon. I think exercise is best when you find modalities that you can stick with and don’t feel like it’s boring or damaging. When I found things I could do during my stationary bike ride like Reed answer Mayo Clinic posts and read the morning Reuters news the hour went by without a thought. I am now sleeping really well at night with constant insomnia over 30 years. For me it’s intuitive because I’ve had a lot of input over the years from medical industry that is knowledgeable and also negligent so I have a good intuition about what might work for me. I listen closely to my doctors, but I don’t give them authority over me if I want more information. I either research it or I go to another doctor. We have to advocate for our self needs. I’ve had many joint replacements and I’m very happy with all of them. I’ve selected my doctors really carefully from lots of references reviews, and talking to people. I chose my medical care doctors at a teaching hospital because that’s where advanced medicine is. I met Ucsd San Diego. However, their bureaucracy for medical care does not make me happy so I take the good with the bad and I just advocate when I need to. but that’s why I have good intuition because I’ve had a lot of experience. Never give up never give in, however, do you take days weeks months off and get reinspired again. Find out what inspires you. I happen to like books a lot. Best wishes for a good outcome.