I used to have terrible problems with numbness in my hands from cycling, so much that I considered buy a recumbent. I tried more padding on my handlebars, moving my hands around more often, and strengthening core muscles. However, the only thing that worked for me was raising the height of my handlebars. When I finally tried that -- raising my handlebars to the same height as my saddle -- the problem went away almost immediately and it's never bothered me since.