One thing that seems to work is to increase your daily intake of pure water.

Just how and why it works is explained here:

http://www.watercure.com/

I know someone who was checking out wheelchairs before he discovered this site.

It was very painful for him to walk and he could barely manage a block before needing to find somewhere to sit down and take a rest.

Six months after finding this site - and starting to drink more water - he was walking up to 2 kilometers and more at a brisk clip and without needing to rest at all.

So it really worked for him.