Shortness of breath is not always a precursor to serious illness. It may be a manifestation of serious illnesses such as heart disease and respiratory disease, or it may be a manifestation of minor illnesses such as functional diseases. 1. Shortness of breath may be present in serious illnesses: (1) heart disease: for example, coronary heart disease, wind heart disease, hypertensive heart disease, dilated or hypertrophic cardiomyopathy, etc., when the occurrence of cardiac insufficiency often appear shortness of breath, chest tightness or palpitations, and the symptoms are aggravated by activities. (2) Diseases of the respiratory system: for example, chronic bronchitis, bronchial asthma, chronic obstructive pulmonary disease, pneumothorax, pleural effusion, or pulmonary space occupation, etc. These respiratory diseases can cause shortness of breath and even dyspnea. 2. Shortness of breath can also occur in mild diseases: If shortness of breath occurs without other medical history, it may be caused by functional factors, such as cardiac neurosis, which is a milder disease. It mostly strikes during bad mood, nervousness, anxiety and other mental abnormalities, which can also trigger symptoms of shortness of breath and chest tightness. All that is needed in this case is to improve your mood, and most people’s shortness of breath symptoms will be relieved without the need for special treatment. When symptoms of shortness of breath occur, it is important to seek medical attention in a timely manner, follow the doctor’s instructions for examination and treatment, and avoid abusing medication, so as not to take the wrong medicine and damage the body.