Smoking is the single most preventable cause of cardiovascular death. Here's what it does — and how fast quitting pays off.
Every cigarette raises your heart rate and blood pressure, stiffens and inflames your arteries, lowers your good (HDL) cholesterol, and makes your blood more likely to clot. Together, those effects roughly double the risk of heart attack — and smoking also drives stroke, peripheral artery disease, and aneurysm.
There is no safe level. Even light or "social" smoking, and regular secondhand exposure, measurably increase cardiovascular risk.
