Make A Move
There are several sports you can do ( and not just for RA!), like: Swimming (preferable in warm water), water-exercises, bicycling, stretching and walking.
You can do these anytime at your own leisure and pace as/when the situation of your condition allows. You don't even have to leave your house for it. Exercise equipment can be purchased at the stores. Even a swimming-pool... if you are swimming in money, haha.
Then we have the slow movement arts: Yoga and Tai Chi.
Anyone at any age can do it. " For people with a variety of musculoskeletal conditions because it improves flexibility and builds muscle strength gradually. And done properly, can be a beneficial exercise for people with arthritis." ( How slow can you go? haha).
Another is Ergotherapy :"Treatment of disease by physical effort." This may help prevent and improve injury, or to give relief to people who already have symptoms.
Physical therapy: "Therapeutic exercise is the systematic implementation of planned physical movements, postures, or activities designed to: 1) remediate or prevent impairments; 2) enhance function; and 3) enhance fitness and well-being."
The therapist will develop a range of exercises solely for you and your condition. Now, if that doesn't make you feel special...:-)
After several years of RA, I had Mensendieck therapy. If I had to describe it, I would say it's a combination of all of the above. I was taught several exercises that I could do myself. I managed to do it for about half a year. Then my RA flared up and I could not do all of them. A good justification I figured for stopping all together. Yeah, yeah, laziness, headstrong, impatience...Take your pick, haha. So, I honestly can not tell you if it helped. Looking back, I think it prolly would have:-)
But let patience have its perfect work, that you may be perfect and complete, lacking nothing.