For the elderly if there is a high pressure high, low pressure low situation, there are usually the following factors: 1, the elderly vascular peripheral resistance increases, for normal people vascular intima belongs to the smooth and fluent, but the elderly will be under the vascular intima, due to physiological reasons, the gradual formation of atherosclerotic plaques lead to vascular sclerosis, arterial elasticity decreases year by year, brittleness gradually increased, which will appear in the blood pressure of the high pressure high, low pressure low situation. The situation of high pressure and low pressure will occur. The pulse pressure difference will also increase accordingly.2. The elderly will experience plaque rupture and chronic hemorrhage with age, resulting in gradual narrowing of the lumen and increase in resistance to blood flow, which will result in high pressure and low pressure increase and decrease in the elderly.3. With the increase of age, the viscosity of the blood will gradually increase, and the patients will experience different degrees of increase in the pulse pressure difference.