Difficulty in breathing while sleeping is usually seen in two situations, as follows: 1. bronchial asthma, which is prone to attack during sleep, that is, at night, because the vagus nerve is relatively excited at night and the bronchi are relatively contracted during the day, thus easily causing airflow restriction and symptoms of dyspnea. 2. cardiac insufficiency, including cardiac insufficiency caused by various reasons, such as Cardiomyopathy, coronary heart disease, hypertensive heart disease and hyperthyroid heart disease, etc. Because the organs in the abdominal cavity move in the direction of the thoracic cavity during sleep, the relative volume of the thoracic cavity should be reduced, the breathing amplitude becomes smaller and restricted, on the other hand, the increase in the amount of cardiac blood return when lying down, the increased load on the heart, which can easily lead to pulmonary stasis, causing respiratory distress. Therefore, if you have difficulty in breathing while sleeping, you should seek early medical examination to clarify the cause.