Exhale long breaths and make sounds due to sadness and depression, feeling unhappy in the heart and other reasons. Comfortable after sighing is seen in children’s plant nerve dysfunction; it can also be in heart disease, accompanied by chest tightness, shortness of breath and other discomfort. Long sigh is a normal physiological phenomenon, people in a calm breathing for a period of time, involuntarily sigh, will have a good role in promoting lung gas exchange. Spontaneous sighing occurs when people think too much or are bored in their hearts, mostly accompanied by a feeling of heavy pressure in front of the chest, but as long as the long sigh, the phenomenon of holding the breath will ease a lot, so feel very comfortable. If “sigh” appears in children, mainly because their nervous system is still in the developmental stage, its function is gradually improving, the control of plant nerves and emotions is not yet stable, once encountered in the external environment of adverse factors, easily induced by plant nerve dysfunction. The incidence of “sighing” will be significantly reduced after the child enters adolescence, as the nervous system matures. When there is heart disease, chest tightness, shortness of breath and sighing will also occur. If you pay attention to your heartbeat and pulse, you may find that your heartbeat or pulse rate is significantly faster or slower than usual, or that you have an irregular rhythm (premature or missed beats), and that you have a cold (fever), cough, sore throat or runny nose), or diarrhea within 2 to 3 weeks before or at the same time as the onset of the disease. If you suspect that you have myocarditis, you should go to the hospital and undergo the necessary tests to get a clear diagnosis and the necessary treatment.