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What Are the Risks of Smoking?

The chemicals in tobacco smoke harm your heart and blood vessels in many ways. For example, they:

  • 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 flow in the leg arteries can cause cramping, pain, weakness, and numbness in your hips, thighs, and calf muscles.

Blocked blood flow also can raise your risk of getting an infection in the affected limb. Your body might have a hard time fighting the infection.

If severe enough, blocked blood flow can cause gangrene (tissue death). In very serious cases, this can lead to leg amputation.

If you have P.A.D., your risk of heart disease and heart attack is six to seven times greater than the risk for people who don't have P.A.D.

Smoking even one or two cigarettes a day can interfere with P.A.D. treatments. People who smoke and people who have diabetes are at highest risk for P.A.D. complications, including gangrene in the leg from decreased blood flow.

Secondhand Smoke Risks

Secondhand smoke is the smoke that comes from the burning end of a cigarette, cigar, or pipe. Secondhand smoke 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 don't smoke in the same way that active smoking harms people who do smoke. Secondhand smoke greatly increases adults' risk of heart attack and death.

Secondhand smoke also raises children and teens' risk of future CHD because it:

  • Lowers HDL cholesterol (good cholesterol)
  • Raises blood pressure
  • Damages heart tissues

The risks of secondhand smoke are especially high for premature babies who have respiratory distress syndrome (RDS) and children who have conditions such as asthma.

Cigar and Pipe Smoke Risks

Researchers know less about how cigar and pipe smoke affects the heart and blood vessels than they do about cigarette smoke.

However, the smoke from cigars and pipes contains the same harmful chemicals as the smoke from cigarettes. Also, studies have shown that people who smoke cigars are at increased risk of heart disease.

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Last Updated: December 20, 2011