Hi Belladonna! I echo a lot of what Beth said in her response. I also have bad knees since my teen years when I was a serious ballet student. I have to be careful about exercise. But I do find that what works well for me is swimming. Are you able to do that, or are you interested in it at all? Some pools have special days for arthritic swimmers where they heat the pool up and offer water exercise classes to older adults or people with arthritis. I always feel happier after I swim. I can't say the same for other forms of exercise so much.