Blood pressure has two peaks in a day, the highest in this time period, the most dangerous when the blood pressure suddenly rises or fluctuates greatly. 1. Highest blood pressure: blood pressure is dynamic change, 6:00 ~ 10:00 in the morning at the peak, 16:00 ~ 20:00 in the afternoon at the peak, generally in this time period blood pressure is easily the highest. 2. The most dangerous: blood pressure suddenly rises or fluctuates the most dangerous, the morning peak blood pressure time period sympathetic nerve excitation, less water intake, high blood viscosity, arterial plaque is easy to fall off, causing cerebral infarction, cerebral hemorrhage and other diseases; evening peak stage blood fluid concentration to the stomach and intestines, cardiac blood output and oxygen consumption increases, inducing angina. Patients with hypertension should take antihypertensive drugs regularly, and also maintain a regular work and rest schedule and a stable state of mind, to control the appearance of blood pressure peaks and keep blood pressure stable, when the patient’s blood pressure suddenly rises or fluctuates greatly, they should consult a doctor as soon as possible for timely treatment.