I have lost weight due to loss of appetite. Do you have access to a pool or treadmill, maybe at a recreation center? Both are good and recommended by my PT. The pool is great! Start out slow on the treadmill, maybe 15-20 minutes and work up slowly. My joints actually feel better if I keep moving. Good luck!
I have gained weight too! So frustrating. Used to run a lot but now running seems to trigger flares. Plus I’ve had to take high dose prednisone several times, which made me gain weight that I haven’t been able to lose all of. I agree with the swimming suggestion, that can feel really nice. I try to walk as much as I can. I really like Zumba too and it doesn’t seem to cause flares for me. Also, I’m trying to shift my exercise schedule from morning (when my RA is the worst) to the evening after work (which is tough because I tend to be fatigued). Anyway good luck! I hope you find something that works for you 😊