Diastolic pressure is when the human heart is diastolic, the arterial blood vessels elastic retraction, the resulting pressure is called diastolic pressure, also known as low pressure 1, heart rate changes have a greater impact on low pressure. When the heart rate increases, the diastolic period is shorter, and less blood flows to the periphery through the small arteries in a shorter period of time, thus increasing the amount of blood flowing in the aorta at the end of diastole, resulting in high low pressure. 2. The elasticity of the arterial wall also has an effect on low pressure. In old age, the collagen fibers of blood vessels proliferate, gradually replacing smooth muscle and elastic fibers, coupled with atherosclerosis, the elasticity of the vessel wall decreases, which reduces the amount of blood returned to the heart and increases the amount of blood stored in the aorta at the end of diastole, resulting in higher low pressure.