During smoking, all kinds of harmful substances are released, including tar and nicotine. Tar is the most important element in the development of cancer. Nicotine quickly enters the bloodstream and has a direct effect on the body. Nicotine narrows blood vessels, speeds up the heart rate and raises blood pressure. The activity of the immune cells in the blood decreases. The consequences of smoking do not only extend to the heart and lungs. All tissues that come into direct contact with tobacco smoke can be damaged.