pg 106...101 tips on Foot Care for People with Diabetes by Jessie H. Ahroni, and Neil M. Scheffler 2nd edition 2006
" Many things can cause cold feet. It may be a sign of poor circulation, but it is not a relieable sign. If you think you have poor circulation, have your feet evaluated by your health care provider.
The best thing to do for cold feet is to wear one or two pairs of thick socks or warm house slippers by check to be sure that your shoes are not too tight. You can try the thin silk socks that are worn under regular socks for added warmth. Getting up and walk around or getting regular exercise helps keep your feet warmer, too.
Do not use heating pads or hot water bottles on your feet. Don't sit too close to a space heater, fireplace, or campfire. If you have any diabetic nerve damage, you cannot feel when your feet are too hot or getting burned, and you could be badly injured.
In addition to making your feet feel cold, nerve damage can affect blood flow and sweating in the feet. People with these problems are not able to release heat from their feet by dilating blood vessels the way someone without nerve damage would. It's best to wear socks and move around from time to time."
If you have a cast on your feet, those slipper socks generally will stretch well over a cast. In addition, taking a bath with the cast is going to be a hassle in and of itself; and it might only last for a bit after the bath anyways.
Even in a wheelchair you can do some exercise. WiiFit if you have it, the boxing can be done from the sitting position, and gives you a sweat. There is also chairdancing. Chair exercises can be looked up online.
I assume you are in the process of discovering your diagnosis. If you do get the diagnosis of diabetic, I would recommend getting a podiatrist on your health care team if your insurance will allow it...and, after your ankle heals see him about care in the future.