When you are leisurely swallowing fog, do you know the hazards of smoking? When you smoke, a lot of harmful substances are inhaled into the lungs with smoke and spread rapidly into the bloodstream, affecting the function of the heart, blood vessels and central nervous system. Nicotine in cigarettes can directly stimulate the vasomotor center, stimulate the release of epinephrine and norepinephrine, causing increased heart rate, peripheral vasoconstriction, blood pressure, these vasoactive substances can also directly damage the vascular endothelium. Nicotine increases blood cholesterol levels and decreases HDL levels to the point where the risk of coronary heart disease increases exponentially. Hemoglobin is the substance that carries oxygen in the blood, but the ability of carbon monoxide to bind to hemoglobin is 250 times higher than oxygen, and once bound, it is not easy to dissociate, and the hemoglobin bound to carbon monoxide loses its ability to carry oxygen. A high concentration of carbon monoxide hemoglobin in the blood can cause a decrease in blood oxygen concentration, insufficient tissue oxygenation, arterial wall edema, endothelial damage, and lipid infiltration into the vessel wall, leading to the formation of atherosclerosis. For patients with coronary artery disease, smoking can accelerate the deterioration of the disease or cause a heart attack, a large number of smoking due to low oxygen and increased excitability of sympathetic nerves, can induce ventricular fibrillation and other serious arrhythmias, becoming one of the causes of sudden death. Smoking is one of the most important risk factors for coronary heart disease, the morbidity and mortality of the disease is 2-6 times higher in smokers compared to non-smokers, and is proportional to the number of cigarettes smoked per day. Smoking increases the risk of coronary artery spasm by 2.4 times. The risk of acute myocardial infarction or sudden coronary death is 2.7 times greater in male smokers and 4.7 times greater in women than in nonsmokers. There is also a significant synergistic hazard effect if smoking and other risk factors are present together. For example, when hypertensive patients who smoked one pack of cigarettes per day stopped smoking, the risk of cardiovascular disease was reduced by 35-40%.