@annsan I have had three of four doses of TC (Docetaxel & Cyclophosphamide) and have walked almost every day. In the week after chemo they are very short walks but I slowly build up, increasing distance & speed. Exercise has been shown to reduce fatigue & side effects of chemo. Separate from that, it's excellent for your mental health. When it's the only thing you do in a day it's a positive activity to hang your hat on.
It has been explained to me here that as this chemo attacks fast growing cells, this includes collagen. Collagen is the chief ingredient of your fascia, which is the connective tissue beneath the skin that attaches, stabilizes, encloses, and separates muscles and other internal organs. Given your existing conditions I would echo @sister's advice and suggest an exercise physiologist. Ask your oncologist for a recommendation, or your GP.
I'm happy to field any questions you have about TC, but bear in mind we all have varied reactions to these drugs. It's a bitter pill we're forced to swallow but it's better than the alternative! You'll get through it, and we're all here to support you. K