Research indicates that cold weather leads to a higher number of heart attacks. Many theories have been developed to explain why this season causes more heart issues. One is that blood vessels constrict due to the drop in temperature. Another theory is that people are not as active in the winter and when they are active, they overexert themselves. That, combined with the constricted blood vessels, leads to disaster. Shoveling is a perfect example of an activity that occurs in cold, winter w...