Shortness of breath is usually a precursor of lung disease, heart disease, chronic disease, etc. It may also be caused by obesity. 1. Lung diseases: For example, tuberculosis, bronchopneumonia, chronic pneumonia, etc. will adversely affect the lung function, resulting in greatly weakened elasticity of the lung tissues and narrowing of the bronchial tubes, and shortness of breath will occur. 2. Heart disease: there are many heart diseases that can lead to shortness of breath, the most common of which are coronary heart disease, heart failure, myocardial infarction, etc. Due to the poor ability of the heart to supply oxygen and blood, shortness of breath will occur. 3. Chronic diseases: chronic diseases such as hemolytic anemia, diabetes mellitus or liver and renal insufficiency and other chronic diseases, patients will have shortness of breath, chest tightness and shortness of breath and other clinical manifestations. 4. Obesity: due to more abdominal fat, the diaphragm up and down activities are limited, affecting the lung respiratory function, shortness of breath symptoms are likely to occur. It is recommended that patients with shortness of breath should consult a doctor in time to clarify the cause of the disease through the doctor’s examination and take effective treatment.