Hi Orchid - I don't know the cause, but I had that problem as well. Then I went to an orientation for a walkathon (60 km 2 day walk for Breast Cancer!!!) that I'm going to be participating in, in September, and the lady mentioned that if your hands swell, which is apparently quite common when doing long walks, that you should carry a water bottle in each hand - just holding something is supposed to help. It's funny because that made me realize that when my hands swelled, it was just the hand that I didn't hold the dog's leash with, because I always took my dog on my walks. So maybe try that - and I'd love to know the cause from anyone else out there!

Have a great day,
Aj