i think it depends how sick u r...if ur at the point where u could go into cardiac arrest without warning then obviously exercising isn't a good idea. i would think if ur physical health is not too bad a little bit of exercise would do u good, after all it's a part of being healthy...the key is moderation, i think, and not pushing urself when exercising. i am an athlete and i found that in actual fact my sport helped me out of my eating disorder b/c it gave me something positive to achieve and i had to eat properly in order to train properly. i think consult a medical doctor to see if u can exercise or not and what is and isn't ok. all the best for ur recovery!