Sleep time "24V DC Cooling Fan" wind should not open too big, in sleep, the body slows down circulation of people, but this time the body most vulnerable when facing the body of excessive wind blowing, it will cause extreme body suited, symptoms of human weakness, and in severe cases a stroke. Should not be long to open "24V DC Cooling Fan", turn fans for too long, the body will produce discomfort phenomenon. With the large body temperature will reduce the evaporation of sweat and the passage of time, it is easy to cause colds, abdominal pain, diarrhea and other symptoms, should be appropriate to open, it is recommended to open time is about one hour is appropriate. Correct placement is very important, fans from the human body should not be too close, too close to the hair so that the blood circulation and sweat circulation gap is too large, the nerve center will be out of balance, once the time is too long, the various organs of the body will feel tired, so general feeling of discomfort. Best of "24V DC Cooling Fan" placement of about two meters away from the body, making even more gentle wind.