In addition to the effects of toxins on the heart and lungs, you are also at risk of cancers, diseases and chronic health problems. Smoking affects the cardiovascular system in several ways. People who smoke are at greater risk of cardiovascular disease, a condition that affects the heart and blood vessels. By smoking, an individual increases their risk of stroke and coronary heart disease; which is the leading cause of death in the United States. A stroke occurs when a clot blocks blood flow to part of your brain when a blood vessel in or around your brain bursts. Even people who smoke fewer than four cigarettes a day may show signs of cardiovascular disease. Other effects of smoking on the cardiovascular system include: increased blood pressure and heart rate, constriction of blood vessels, decreased oxygen carried in the blood, damage to the lining of the arteries, and reduced blood flow to the ends. The second best known is the respiratory system. Smoking can harm the functioning of the respiratory system. The mucus formed by the respiratory tubules traps dirt and disease-causing organisms, which the cilia sweep near the mouth, where they can be eliminated; smoking impairs this process. Because cigarette smoke is acidic and contains many different chemicals, it can cause irritation of the lining of the bronchi and bronchioles, known as chronic bronchitis. The mucous membrane then becomes inflamed and swollen and can also become infected. Every time you smoke, you can make the irritation worse. This can last for months or even years, causing shortness of breath, coughing, and chest pain. The majority of respiratory cancers are attributed to smoking. The tar in cigarette smoke can coat the lining of the alveoli and will significantly increase the risk of emphysema. According to the British Pharmaceutical Industry Association, "smoking