Girls suddenly out of breath may be the result of the following aspects: First, girls are prone to emotional anxiety, tension, easily caused by mood swings, which can easily cause open-mouth breathing, respiratory alkalosis, which can also cause sudden shortness of breath. Second, girls suddenly out of breath may also be related to lung disease, to exclude pneumothorax, especially girls with long and lean body type, shortness of breath and breathlessness after strenuous exercise is recommended to go to the hospital to do a chest X-ray to exclude pneumothorax. Third, if it is sudden shortness of breath after exercise, also pay attention to exclude heart disease, improve the electrocardiogram, cardiac ultrasound examination.