I was running my afternoon double yesterday, when I came across the city blood bank. I then pondered whether if blood type (O-, A+, AB+, B-, etc.) has anything to do with natural talent and/or potential in distance running. Maybe it doesn't make a difference. I don't know. Thanks to wikipedia (http://en.wikipedia.org/wiki/Blood_type), I now comprehend the differences among blood types but was unable to find my answer. After some more searching, I still have no answer to my question. Does anyone know if one kind is more advantage to endurance training, whether it's running, biking, swimming, etc.? If so, why?