Thicken your blood and make it harder for your blood to carry oxygen.
Increase your blood pressure and heart rate, making your heart work harder than normal.
Lower your HDL cholesterol (sometimes called "good" cholesterol) and raise your LDL cholesterol (sometimes called "bad" cholesterol). Smoking also increases your triglyceride level. Triglycerides are a type of fat found in the blood.
Disturb normal heart rhythms.
Damage blood vessel walls, making them stiff and less elastic (stretchy). This damage narrows the blood vessels and adds to the damage caused by unhealthy cholesterol levels.
Contribute to inflammation, which may trigger plaque buildup in your arteries.
Smoking and Heart Disease Risk

Smoking is a major risk factor for coronary heart disease (CHD). CHD is a condition in which plaque builds up inside the coronary arteries. These arteries supply your heart muscle with oxygen-rich blood.

When plaque builds up in the arteries, the condition is called atherosclerosis.

Plaque narrows the arteries and reduces blood flow to your heart muscle. The buildup of plaque also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow.

Over time, smoking contributes to atherosclerosis and increases your risk of having and dying from heart disease, heart failure, or a heart attack.

Compared with people who don't smoke, people who smoke can be up to two to three times more likely to have heart disease and twice as likely to have a heart attack. The risk of having or dying from a heart attack is even higher among people who smoke and already have heart disease.

For some people, such as women who use birth control pills and people who have diabetes, smoking poses an even greater risk to the heart and blood vessels.

Smoking is a major risk factor for heart disease. When combined with other risk factors—such as unhealthy blood cholesterol levels, high blood pressure, and overweight or obesity—smoking further raises the risk of heart disease.

Any amount of smoking, even light or occasional smoking, harms your body. Research suggests that smoking can even cancel out the benefits of other efforts to reduce heart disease risk, such as taking aspirin or medicines to lower cholesterol.

Smoking and Peripheral Arterial Disease Risk

Peripheral arterial disease (P.A.D.) is a disease in which plaque builds up in the arteries that carry blood to your head, organs, and limbs. Smoking is a major risk factor for P.A.D. Your risk of P.A.D. increases by four if you smoke or have a history of smoking.

P.A.D. usually affects the arteries that carry blood to your legs. Blocked blood