Table of Contents
Smoking as a cause of Cardiovascular disease
CARDIOVASCULAR DISEASE (CVD) is the most frequent and significant consequence of cigarette smoking, with smoking accounting for one in six deaths due to CVD. Smoking significantly increases the risk for HYPERTENSION (high BLOOD PRESSURE), ATHEROSCLEROSIS, and CORONARY ARTERY DISEASE (CAD). The combination of cigarette smoking and using oral contraceptives (birth control pills) presents a particular risk of BLOOD clot formation in women, especially women over age 35. This raises the risk for STROKE and HEART ATTACK such that many doctors will not prescribe oral contraceptives for women who smoke. Smoking is also a key factor in numerous pulmonary diseases, affecting the cardiovascular system’s ability to circulate oxygenrich blood.
The US Surgeon General offered the first conclusive evidence of the correlations between smoking and cardiovascular disease in the landmark 1964 report, Smoking and Health: Report of the Advisory Committee to the Surgeon General of the Public Health Service. Researchers have since continued to accumulate knowledge and understanding of the mechanisms through which smoking affects cardiovascular health. Cigarette smoke contains more than 2,000 identifiable chemicals, dozens of which are carcinogenic (CANCER-causing) or have other deleterious actions on health. Two in particular, NICOTINE and carbon monoxide, are highly toxic to the cardiovascular system.
Nicotine and Cardiovascular Function
NICOTINE is a CENTRAL NERVOUS SYSTEM stimulant that acts on nerves throughout the body. In the cardiovascular system, nicotine stimulates the nerves that regulate smooth MUSCLE tissue, causing smooth muscle cells to contract. This constricts blood vessels, notably arteries, reducing the channel for blood flow. Nicotine further stimulates the baroreflex sensors (clusters of NERVE cells in the major arteries and the heart that sense the flow and pressure of blood). These actions result in increased blood pressure, HEART RATE, and cardiac workload. Nicotine further acts as an irritant within the arteries, causing INFLAMMATION of the inner layer of the arterial wall. Researchers believe such inflammation may be the foundation for atherosclerosis.
Carbon Monoxide and Cardiovascular Function
Carbon monoxide is a poison. It has a greater affinity than oxygen for HEMOGLOBIN and binds with hemoglobin, blocking hemoglobin from carrying oxygen. This reduces the amount of oxygen that enters the bloodstream from the LUNGS. By the end of a cigarette, a smoker can have concentrations of carbon monoxide as high as 7 percent; 10 percent is the level at which symptoms of carbon monoxide poisoning begin to become apparent. Carbon monoxide in the bloodstream deprives cells in the BRAIN and heart, which rely on oxygen for fuel.
Environmental Smoke Exposure
Cigarette smoke also raises the risk for health problems, including cardiovascular disease, among people who are themselves nonsmokers though live or work in a smoking environment. Children are at particular risk. Numerous studies show the children of smokers have more EAR infections, sinus infections, and upper respiratory infections than children who live in smoke-free environments. Long-term exposure to ENVIRONMENTAL CIGARETTE SMOKE, called passive smoking, has the same health consequences as active smoking.
The health risks of cigarette smoking diminish within 30 to 40 minutes of the last puff. With sustained SMOKING CESSATION, the risk for cardiovascular disease gradually diminishes over 5 to 10 years, finally reaching a level consistent with the risks for a nonsmoker. Any damage that has already occurred to the cardiovascular system is permanent, however.