Smoking is a major risk factor for heart disease. It contributes to the buildup of plaque in your arteries, increases the risk of blood clots, reduces the oxygen in your blood, increases your blood pressure and forces your heart to work harder. When combined with other risk factors—including elevated blood cholesterol levels, high blood pressure, and overweight/obesity—smoking further increases your risk of heart disease and/or stroke.
Even light or occasional smoking damages the heart and blood vessels. For some people, such as women who use birth control pills and people who have diabetes, smoking poses an even greater risk to the health.
Secondhand smoke can also harm the heart and blood vessels. (Secondhand smoke is the smoke that comes from the burning end of a cigarette, cigar, or pipe, and also refers to smoke that’s breathed out by a person who is smoking.)
Secondhand smoke contains many of the same harmful chemicals that people inhale when they smoke. It can damage the hearts and blood vessels of people who do not choose to smoke in the same way that active smoking harms people who do. Secondhand smoke greatly increases an adult’s risk of heart attack and death and also raises children’s and teens’ risk of future heart disease, because it lowers HDL (good) cholesterol, raises blood pressure, and damages the tissues of the heart.