In addition to the effects of toxins on the heart and lungs, there is also the risk of cancers, diseases and chronic health problems. Smoking affects the cardiovascular system in many ways. Individuals who smoke are at increased risk of cardiovascular disease, a disease that affects the heart and blood vessels. Smoking increases an individual's 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 the brain when a blood vessel in or around the brain bursts. Even individuals who smoke fewer than four cigarettes a day may show signs of cardiovascular disease. Other effects of smoking on the cardiovascular system are; increased blood pressure and heart rate, constriction of blood vessels, less oxygen transport in the blood, damage to the lining of the arteries and reduced blood flow to the extremities. The second best known is the respiratory system. Smoking can cause damage to the respiratory system. The mucus formed by the respiratory tubules traps dirt and pathogenic organisms, which the cilia sweep close to the mouth, where they can be removed; smoking hinders this process. Because cigarette smoke is acidic and contains so many different chemicals, it can cause irritation to the lining of the bronchi and bronchioles, known as chronic bronchitis. The lining then becomes inflamed and swollen and can even become infected. Every time you smoke you can increase irritation. This can last for months or even years and causes shortness of breath, coughing and chest pain. Most respiratory cancers are attributed to smoking. The tar in cigarette smoke can coat the lining of the alveoli and significantly increases the risk of emphysema. According to the Association of the British Pharmaceutical Industry, “Smoking