Quit smoking 24 hours the body will have mood, sleep bad abnormalities, as well as physical discomfort and other withdrawal reactions. 1. Emotional and sleep abnormalities: Cigarettes contain nicotine, which makes people dependent. When dependence is formed and then suddenly quit, it will trigger withdrawal symptoms. Nicotine increases the excitability of nerve cells, and when a large number of cigarettes are smoked, the cells will first become excited and then become inhibited. When the nicotine level in the body decreases after 24 hours of quitting smoking, abnormal withdrawal reactions of the nervous system will occur, such as boredom, irritability, lack of energy, insomnia, easy to wake up and other symptoms. 2. Physical discomfort: After 24 hours of smoking cessation, when the nicotine and carbon monoxide content in the body decreases, the circulatory system of the whole body will be improved, the oxygen supply of the body will gradually become normal, and the blood pressure and pulse rate will tend to stabilize. The ciliated cells in the lungs also begin to repair and regenerate, removing mucus and harmful substances from the body, and frequent coughing and phlegm may occur.