Severe cold in North India increases the risk of heart attacks and strokes, as colder weather constricts blood vessels, raising blood pressure and reducing oxygen flow to the heart. Dr. Naresh Trehan advises preventive measures, noting that factors like sudden cold exposure, hypothermia, reduced sunlight impacting mental well-being, urban lifestyle habits, and increased alcohol or smoking consumption further elevate risks during winter. Individuals with pre-existing conditions like high blood pressure or cholesterol are particularly vulnerable.