Antoniette, there is no reason you cannot exercise now. You just need to be careful not to push it in areas that are currently in pain.
My thoracics can also get very bad, but I always found that pilates helped a great deal. You might want to look into a good pilates class, making sure that the teacher can work with you to adapt exercises based on your condition on any given day and/or to take into account that there are one or two pilates exercises that we with AS should not do. I only do pilates matt work and even if I only do my warm-ups my thoracics always feel better afterward. You will find that the range of motion and stretching involved with pilates, not to mention the breathing technique that's involved, will help a great deal.
I also do cardio, but use the elliptical because it is not hard on my joints; there's no impact, you see, because your feet never leave the pedals. I also walk everywhere I can. Swimming in a warm water pool will also be of great value to you.
And I do weight training - for muscle toning not muscle building - low weights, high reps. Shoulders and legs one day, triceps and chest the next, biceps and back the next. I never work the same area two days in a row (ie shoulders & back). Listen to your body, if your shoulders hurt, don't do shoulders that day. If your knees are bad, don't do legs. You may find that if you're careful, you will feel much better overall for doing weight training.
Flexibility exercise is of great importance to us. Again, however, don't overstretch an area that has pain. If it feels tight, that's one thing; if there's frank pain, that's a completely different kettle of fish. My usual advice to anyone with arthritis who is starting a fitness program is to work it up extremely slowly.
Work your way up to 15 minutes in one go of stretching/flexiblity (5 minutes at a time 3 times a day to start, for instance, and working it up from there to a full 15 minutes at a shot). Once you can do that, then start with strengthening/weight training. Take it extremely slowly, listen to your body. Once you can do 15 minutes of that plus 15 minutes of stretching, then add the cardio. By that time your muscles will be accustomed to the work and you won't injure yourself doing the cardio. If you can only do 1 minute of cardio at a go, then do 1 minute, 15-20 times a day. Build it up slowly to 15 or 20 minutes at a go.
The mistake alot of people seem to make is that they push it too much after a prolonged period away from exercise (or if they've never exercised). You cannot do the entire Jane Fonda workout the first time out, if you know what I mean. The other mistake is working through the pain. I do this, but only if the pain is light and I've learned to tell the difference between pain that is telling me to back off and pain that is sitting in the background complaining for lack of use. Not sure if I worded that clearly.
I am no doctor, nor a physio-therapist, nor a fitness expert, but these are the guidelines that have worked for me. I hope they help.
Hugs,
