With the recent significant drop in temperature, people can easily get cold and develop respiratory diseases. In particular, the elderly and children with poor resistance, patients with chronic respiratory diseases (such as chronic obstructive pulmonary disease, asthma, bronchial dilatation and other diseases), chronic heart disease, diabetes and other diseases are more likely to suffer from acute attacks or respiratory diseases as a result. The sudden drop in temperature is also a time of high incidence of cardiovascular diseases. Therefore, it is recommended to add clothes in time as the temperature drops. Some places have air conditioning or heating, resulting in a large difference between indoor and outdoor temperatures, and clothing should be increased or decreased in time with temperature changes. In particular, patients with pre-existing underlying diseases should pay more attention to keeping warm in winter and wear masks and scarves when they go out. Increased nutrition can also effectively improve immunity. For example, eat more fruits and vegetables rich in vitamins, such as tomatoes, cabbage, apples, pears, bananas, etc. For residence and office space should be properly ventilated, pay attention to keep the air fresh. Some people are reluctant to open windows because of the cold, and the turbid air increases the chances of spreading diseases, especially respiratory diseases. When you go out, you should try to go to less crowded places, reduce unnecessary gatherings, and try not to contact with flu patients to reduce the spread of diseases. You should also be careful to wash your hands regularly and not to use your hands to pick your nose or rub your eyes to avoid infections caused by pathogens carried on your hands through these actions. In addition, the bedding should be dried regularly, the ultraviolet rays of the sun can play a role in sterilization. Physical exercise is also important, at least three times a week, 30 to 45 minutes each time, the project can vary from person to person, such as walking, running, playing ball, doing exercises, practicing tai chi, practice sword, dancing, etc.. But exercise should be careful to avoid the cold period, outdoor sports should also pay attention to avoid injuries caused by icy roads, not excessive.