Systolic Blood Pressure
As blood is pumped from your heart into your blood vessels, enough systolic blood pressure is created to send it to all other parts of your body. As blood vessels travel away from the heart, they branch off and gradually get smaller -- just like a tree's branches. One branch may go to the brain while another may go to your kidneys. Systolic blood pressure keeps blood flowing through the branches so that your body's cells get the oxygen and nutrients they need and waste matter can be removed.
If the systolic pressure is too low (known as hypotension or low blood pressure), the blood is not able to bring oxygen and nutrients to the body's cells and remove waste matter. This can cause the cells to die. The systolic blood pressure is considered low when the blood pressure reading is below 90.
If diastolic and systolic blood pressures are both too high, a person is said to have high blood pressure, which is also known as hypertension. With high blood pressure, the average systolic blood pressure reading is higher than 140 and the average diastolic blood pressure reading is higher than 90. If only the systolic blood pressure is higher than 140, the person has a condition called isolated systolic hypertension.
In people with high blood pressure, the small blood vessels in the vital organs are most affected over time. These blood vessels become scarred, hardened, and less elastic, meaning that they are more likely to get blocked or rupture (leading to organ damage or even failure). This may happen as you get older, whether or not your blood pressure is too high, but high blood pressure can speed up this process. Keeping a normal blood pressure is an important part of reducing the risk of: