What Causes Sweating Just After A Short Walk?

I regularly go to the gym and weight train and am in good shape. However, I wouldn t say that I am fit with respect to cardio. When I walk, like out to the shops etc (which i rarely do as I drive most often), i work up a real sweat. Is this just a fitness thing? If I become more cardio fit, will I sweat less when I walk about? I have read the fit people sweat easier, but Im not talking in respect to full exertion exercise, rather just walking about town.