I know someone like Jill does, where the person's blood cells have a little different make-up so the blood has a harder time traveling to the extremeties of the body, like hands, fingers, toes and feet. Even extra excersize doesn't help with this, because the blood just doesn't flow to the areas. So,...always have mittens and extra socks. That's what my friend does...even if it's a cold summer day, I notice that sometimes, she'll have her shirt pulled over her hands to keep them warm. And, she doesn't wear sandles very often because her feet are often cold, even on warm days.