Nicotine and carbon monoxide are the main culprits, but there are over 400 other harmful ingredients. In general, tobacco use increases the work load of the heart and is the major cause of premature death from heart disease.
Smoking is particularly risky for people who have heart disease or high blood pressure.
Tobacco products raise blood pressure, increase the heart rate, narrow arteries, and decreases the blood supply to the heart. Smoking also causes abnormal blood clotting and the build up of fatty material called plaque, which cause coronary artery and peripheral vascular disease. Most tobacco users are aware of the health risks, and most smokers want to quit. But quitting is not easy, because tobacco habits are physically and emotionally satisfying. Nicotine addiction has been identified as the main reason that people continue to use tobacco.