I've been racing bicycles competitively for more than three years now. About ten months ago I developed a numbness in my feet that would occur after about an hour of riding. My family doctor does not think it is a problem with circulation but rather with nerves. At first I thought my shoes and pedals were the problem. But switching them and trying different insoles has not helped. I'm also convinced that it is not an equipment (i.e. pedals or shoes) problem since my feet go numb after only twenty minutes on the cross country skiing machine at the gym (while wearing comfortable running shoes).
What's wrong with my feet? What can I do?