Exercise is highly recommended for those suffering from ulcerative colitis. Of course, choose the gentlest form of exercise. Yoga is always a great choice, but if you feel that you can't adequately work out those arms with such a low-key regimen, just jump it up a notch by using one of those portable elastic bands, which you can use in your own personal gyms. I don't even own a membership to a gym, for I never know when my symptoms are going to flare up. Why deal with the traffic and hassle of a gym, when you can work out at home?
One of the first exercises I engage in is the bicep curl. I stand on the midpoint of the elastic band with both feet, with the handles in both hands. I then slowly concentrate on my bicep muscles, try to “isolate” them through focus and concentration, and pull up the handles towards my shoulders-focusing on using my bicep muscles exclusively to this. I do a few slow reps, actually no more than ten, since I'm rather lazy, and I'm done for the day.
I then do an overhead press, to work those muscles along the back of the arms. I've been getting a bit soft back there thanks to disuse. So again, I stand on the band, hold the handles up to over my shoulders, with my palms facing inward. I then “push” my hands upwards with those back muscles, feeling my arms tighten, and then I lower. I have been trying to get a few more repetitions of these in whenever I can.
You really don't need to do much to work out your arms. I keep these exercises as part of my daily routine. I also push on various pressure points along the arms, and find that not only does this help keep my internal balance, but it also has made my arms less puffy (probably due to the increased blood flow to them). I push on the web between my thumb and index finger, along my wrists and inner arms, the backs of my upper arms, and in the crease of my inner elbow. This final point can be found by bending your arm, and pressing the point in the “L-shaped” region of the bend.