Holding the breath for one minute indicates normal lung function, but as there may be errors, it is recommended to combine with other auxiliary tests to comprehensively assess the lung function. 1. Clinically, the method of taking several deep breaths, then taking a deep breath, holding the breath, and recording the time of holding the breath is called the breath-holding test. During the breath-holding period, the partial pressure of carbon dioxide in the alveolar air gradually rises and the partial pressure of oxygen in the arterial blood gradually decreases, thus causing a series of abnormal reactions in the respiratory, circulatory and central nervous systems. 2. The breath-holding test is used to initially assess the cardiopulmonary function. Generally speaking, if you can hold your breath for more than 30 seconds, your cardiopulmonary function is normal, and when the breath-holding time is less than 20 seconds, it suggests that your cardiopulmonary function is not complete. 3. However, due to the many factors affecting the test, the results of the test may be affected by different individuals or hypoxia tolerance training. It is recommended to consult a specialist and combine the results of pulmonary ventilation + ventilation + airway resistance + reversibility test as the gold standard for pulmonary function tests.