Electric fans can easily cause colds if blown for a long time, especially after falling asleep, and in addition to causing colds, they may also cause local muscle pain and damage to joints. Often a long time blowing fan is easy to cause arthritis, but also will take away the body surface of the moisture, there will be local skin dryness. Some people blowing for a long time may also cause nausea, vomiting and general weakness, so you should try to avoid blowing the fan for a long time, especially after falling asleep at night. If the temperature is particularly hot in summer, you can adjust the wind speed of the fan to be smaller or use a miniature fan, which will have less impact on human health and will increase the comfort level.