Normal values for blood pressure in the morning are generally 90-139 mmHg for high pressure (systolic) and 60-89 mmHg for low pressure (diastolic). Blood pressure is used to reflect the pumping of blood by the heart, the elasticity of blood vessels and the peripheral resistance of blood vessels, etc. The high pressure value reflects the pressure of blood on the side walls of blood vessels when the heart is pumping. Low blood pressure reflects the pressure of blood on the walls of blood vessels when the heart is in diastole. There are five main factors that affect blood pressure: 1. per-pulse output, which mainly affects systolic blood pressure. When per-pulse output is increased, systolic blood pressure increases, and the determining factor of systolic blood pressure is per-pulse output. 2. peripheral vascular resistance, it is the peripheral vascular resistance that is obvious to the diastolic blood pressure, when the peripheral vascular resistance is greater, the diastolic blood pressure will rise accordingly. 3. Elasticity of the aorta, if the elasticity of the arteries decreases and the brittleness of the aorta increases, the blood pressure will rise, with the systolic blood pressure rising most significantly, and the diastolic blood pressure will not rise as significantly as the systolic blood pressure. 4. Heart rate. When the heart rate increases, diastolic blood pressure rises, as does systolic blood pressure, but diastolic blood pressure rises more significantly. 5. Effective circulating blood volume, if the patient has insufficient effective circulating blood volume such as shock, it will also lead to a drop in blood pressure. The body’s blood pressure regulation mechanism is complex and has a certain relationship with the measurement method, so it is necessary to measure blood pressure in order to clarify whether the blood pressure is abnormal.