REDUCING YOUR RISK OF CORONARY ARTERY DISEASE: SMOKING- WHY IS SMOKING HARMFUL? WHAT CAN IT CAUSE?
Smoking may cause ischemia (lack of oxygen and blood flow to the heart muscle) by transiently decreasing the diameter of the coronary arteries. When arteries that are already narrowed by atherosclerotic deposits become narrowed even further, blood flow to the heart muscle may be reduced enough to cause angina or a heart attack. When smokers with angina exert themselves, they get chest pain sooner than they would otherwise, because smoking reduces the amount of oxygen to the heart and also makes the heart beat faster. So, ironically, the heart’s demand for oxygen increases and the supply of oxygen decreases. Smoking blocks the increased blood flow that normally occurs with exercise and reduces the effectiveness of some anti-anginal drugs. Even in the absence of symptoms, studies have shown that there is evidence of myocardial ischemia during smoking. In some cases, smoking can cause coronary arteries without atherosclerosis to go into spasm and narrow enough to cut off blood flow to the heart muscle.The heart and coronary arteries are not the only cardiovascular targets of smoking damage. Smoking is a major risk factor for peripheral vascular disease (atherosclerotic narrowing of the blood vessels that carry blood to your arm and leg muscles). The consequences may range from the exertion-related pain of claudication (see page 98) to the actual destruction of skin or muscle tissue supplied by blocked arteries. When severe, this condition may require operation or amputation. Women who smoke and take birth control pills place themselves at higher risk for another serious vascular problem—stroke.Smoking is the main cause of chronic lung diseases such as chronic bronchitis and emphysema, which put an additional strain on the heart.*230\252\8*
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