Shortness of breath is a subjective symptom, people subjectively feel that they can’t inhale or feel that they can’t exhale, resulting in short breathing time, causing shortness of breath due to a number of reasons are as follows: 1, the most common respiratory diseases, such as bronchial asthma, chronic obstructive pulmonary disease, pulmonary embolism, and interstitial lung disease, etc. 2, cardiac reasons, such as hypertension heart disease, coronary heart disease, hyperthyroidism, mitral stenosis, and various other causes of heart disease can lead to a decline in heart function, resulting in shortness of breath symptoms. 3, caused by mental factors, some people may experience symptoms under emotional excitement or other mental influences.4 As well as other causes of heart disease can lead to a decline in cardiac function, resulting in shortness of breath symptoms. 3, caused by mental factors, some people in emotional excitement or other mental influence, shortness of breath symptoms. 4, caused by various reasons of fever, high body temperature can lead to respiration and heartbeat accelerate at the same time increase in oxygen consumption, shortness of breath symptoms can occur. Therefore, if you have shortness of breath for a long period of time, you should consult a doctor in time to have the appropriate examination to clarify.