Air conditioning in winter may cause colds. If you turn on a warm air conditioner in winter, the temperature difference between indoors and outdoors will be too big, and it will be cold for a while and hot for a while, which will easily cause a cold. Air-conditioned rooms are very airtight, so there is no exchange of air between indoors and outdoors. Indoor air is prone to viruses, bacteria, and other harmful microorganisms, and the air quality is poor, which makes it easy to catch a cold. It is recommended not to stay in the air-conditioned room for a long time in winter. Open the windows frequently to keep the air circulating. At the same time, clean the air conditioner regularly to avoid breeding some viruses and bacteria, otherwise it is easy to lead to the occurrence of colds. In addition, in the air-conditioned room to drink more water, so that the throat to keep moist, or turn on the humidifier, so as to avoid dry throat and other situations.