mouse1,

Try using a chair exercise pedal system. It may help to have less body movement while you are exercising. Here is a link showing what I am referring to. http://www.walmart.com/ip/Carex-Pedal-Exerciser/6537516

I use to walk in a pool. It is less jarring than walking on hard surfaces. I'd walk for 50 minutes and go almost a mile. I also did a breast stroke through the water to get some upper body exercise.

You can also try walking with ear plugs in. This helps you hear your foot plant. It will surprise you at how much jarring travels to your head. You can use this to learn a softer foot plant so your head is not jarred.

My best to you.