Sleeping on the left side of the heart with a sense of pressure may have a variety of circumstances, may be a normal physiological phenomenon, may also be due to anxiety, nervousness and other emotions, but also by disease (such as coronary heart disease, angina pectoris, cardiac insufficiency, etc.). 1. Normal physiological phenomenon: when lying on the left side, the left side of the heart has a feeling of pressure due to the compression of some nerves by the body when sleeping and lying down, which can be improved by changing the sleeping position. 2. Nervousness, anxiety: through the examination (such as echocardiography, electrocardiogram, etc.) to rule out organic damage to the heart, the pressure may be due to nervousness and anxiety caused by the feeling of pressure, can be without special treatment, try to relax the mood. 3. Coronary heart disease, angina pectoris: if prone angina pectoris occurs, the feeling of pressure on the heart will appear during sleep, and 24-hour ECG and coronary CTA should be examined in time to see if prone angina pectoris occurs. 4. Cardiac insufficiency: For patients with heart failure and cardiac insufficiency, as they sleep in the lying position, the volume of return blood increases, causing deterioration of cardiac function, resulting in a feeling of pressure on the heart, echocardiography, electrocardiogram, BNP and other tests should be conducted to find out whether cardiac insufficiency occurs. When there is a feeling of pressure on the left side of the heart when sleeping, you should go to a regular hospital in time and be treated under the guidance of a doctor.