"Waterproof Cooling Fan" to open the wind speed should not be too large, so that the human body has a process of adaptation. Indoor wind speed is best controlled at 0.2-0.5 m / sec, especially in ventilated rooms and in places there are, fans of the wind speed but can not be too large. "Waterproof Cooling Fan" who should not be facing the wind, blowing straight, invade the body, especially in frail or sweating, it is best to let a fan blow in one corner. Children, elderly, frail people, but should use less fan blowing, but can regulate indoor air fans, thereby indirectly cooling. When the dripping sweat but can not direct access to fan blowing, so as not to cause surface perspiration disorders, leading to destruction of the human circulation, it is easy to cause a stroke. "Waterproof Cooling Fan" sleep when the wind should not open too big, people sleep, the human circulation slows down, and this time the body is most vulnerable when facing the body of excessive wind blowing, it will not cause human extreme adapt, symptoms of human weakness, and in severe cases a stroke.