Seven-year-old girls often breathlessness is mainly considered to have heart, lung or blood system diseases, such as congenital heart disease, myocarditis, bronchial asthma, anemia and so on. 1. Heart disease: such as congenital heart disease, myocarditis, etc., can make the patient’s heart muscle damage, resulting in a decrease in the heart’s pumping ability, the whole body blood supply and oxygen supply is insufficient, showing easy to strain, easy to infection, dyspnea and other symptoms. 2. Lung disease: If you suffer from bronchial asthma, when you encounter a little cold or slightly stimulating gas, you can appear wheezing and coughing, dyspnea and other symptoms. 3. Blood system diseases: when children have anemia, due to the decrease of hemoglobin, resulting in the decrease of oxygen carrying capacity of the blood, there is a lack of oxygen supply to the whole body, showing weakness of breathing, easy to fatigue, dizziness after exercise and other symptoms. Parents should bring their children to the hospital in time to avoid delaying their condition if they find that their children are often out of breath.