Doing breath-holding exercises can increase lung capacity and increase the body’s tolerance to hypoxia. 1. can increase lung capacity: often do breath-holding exercise, can increase lung capacity. It can enhance the contraction force of the lungs. 2. can increase the body’s ability to adapt to hypoxia: for example, people who often dive to do this exercise, hold their breath after going into the water, come up from the water to breathe. If the ability to tolerate hypoxia is poor, the ability to dive will decline. Do breath-holding exercise to pay attention to safety, cardiopulmonary insufficiency patients are not suitable to do breath-holding training, excessive physical weakness, anemia, serious patients may not do breath-holding exercise, to avoid aggravating the condition. Do breath-holding training if discomfort occurs, we must promptly consult a doctor, do not self-medication, under the guidance of a physician to standardize the treatment.