Multiple Sclerosis and Exercise

Hello all!

I have MS. My MS gets particularly aggravated when my body temperature rises, which obviously poses a conundrum when trying to exercise for weight loss and overall health - which is especially important to slow the MS progression. My feet go totally numb when I get too warm. Add that to my already existing balance issues from the MS, and if I get on an elliptical, treadmill, etc. - anything involving standing, really - and it's a recipe for a broken limb.

Here's my question: other than water exercise/swimming and stationary bikes, what cardio options do I have that won't leave me on crutches?

Note: I live in Tennessee, so extended outdoor exercise in the summer is out. I have a prescribed cooling vest, and it's better than nothing, but I still get the numb feet issue, though to a lesser degree. I've talked to my Dr., and he's given me no restrictions, just FYI.