Decreased labor tolerance often occurs in chronic pulmonary heart disease, which is a heart disease caused by chronic lesions of the lungs, thorax or pulmonary arteries that increase the resistance of the pulmonary circulation, resulting in pulmonary hypertension and right ventricular hypertrophy, and finally right heart failure, referred to as pulmonary heart disease. Its clinical features include cough, sputum, palpitation after activity, dyspnea, swelling of the lower limbs, emphysema and dilated pulmonary artery branches on X-ray, and enlarged right atrium or right ventricle on echocardiography. The course of the disease is slow, firstly, patients have a long history of chronic cough, sputum or asthma, and gradually develop weakness and dyspnea, followed by palpitations, increased shortness of breath and cyanosis, especially in the case of acute respiratory infections, ventilation disorders are further aggravated, which causes hypoxia and carbon dioxide retention and leads to respiratory failure and heart failure. This disease is more common in China, and according to domestic statistics in recent years, the average prevalence of pulmonary heart disease is 0.41%-0.47%. The age of the disease is mostly above 40 years old, and the prevalence increases with age. Acute attacks are more common in winter and spring. Acute respiratory infections are often the cause of acute attacks, often leading to pulmonary and cardiac failure and a high mortality rate. The etiology of decreased labor endurance: According to the different parts of the primary disease, it can be divided into three categories: 1, bronchial and pulmonary diseases Slow branch complicating obstructive emphysema is the most common, accounting for about 80%-90%, followed by bronchial asthma, bronchiectasis, severe tuberculosis, pneumoconiosis, chronic diffuse interstitial pulmonary fibrosis, nodular disease, allergic alveolitis, eosinophilic granuloma, etc. 2, thoracic motility disorders Less common, severe posterior spine, scoliosis, spinal tuberculosis, rheumatoid arthritis, extensive pleural adhesions and severe thoracic or spinal deformities caused by post-thoracic formation surgery, as well as neuromuscular disorders such as poliomyelitis, can cause restricted thoracic corridor activity, pulmonary compression, bronchial distortion or deformation, resulting in restricted pulmonary function, poor airway drainage, recurrent pulmonary infections, complicated by emphysema or fibrosis, hypoxia, pulmonary vasoconstriction, narrowing, which increases resistance, pulmonary hypertension, and development of pulmonary heart disease. 3, pulmonary vascular disease Very rare. Allergic granulomatosis involving the pulmonary arteries, extensive or recurrent multiple small pulmonary artery embolism and small pulmonary arteritis, and primary pulmonary hypertension of unknown origin can narrow and obstruct the small pulmonary arteries, causing increased pulmonary vascular resistance, pulmonary hypertension, and increased right ventricular load, leading to the development of pulmonary heart disease.