Blood pressure is the amount of force (pressure) that blood exerts on the walls of the vessels as it passes through them.
As blood is pumped from your heart into your blood vessels, enough 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 the branches of a tree. One branch may go to the brain, while another may go to your kidneys. Blood pressure keeps the blood flowing through all these branches so your body's cells get the oxygen and nutrients they need.
When
measuring blood pressure, a fabric cuff fabric is wrapped around your arm and then slightly inflated. The blood pressure shows up on a gauge attached to the cuff. The healthcare provider reads the numbers from the gauge as air is released from the cuff. This device used is called a
sphygmomanometer. Blood pressure can also be measured with a special machine.
The two numbers that measure your blood pressure are written like a fraction: one number on top and one on the bottom. For example, what many people consider
normal blood pressure is read as 120/80. The number on top is called the systolic pressure. It measures the pressure inside your blood vessels at the moment your heart beats. The number on the bottom is your diastolic pressure. It measures the pressure in your blood vessels between heartbeats, when your heart is resting.
Blood Pressure and Blood Vessels
When your heart contracts, the pressure in your blood vessels goes up as the blood passes through. When your heart relaxes in between heartbeats, the pressure inside your blood vessels goes down. In order to push the blood to all your vital organs, you need healthy, elastic blood vessels that stretch and shrink as the pressure goes up and down.
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, which means 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. High blood pressure can speed up this process, so keeping it at a normal level is an important part of reducing the risk of:
Factors Affecting Blood Pressure
Blood pressure changes frequently throughout the day. Factors that can make it change within just a few minutes include:
- Posture
- Level of exercise
- Amount of tension
- Nicotine use.
It's easy to see why a person's blood pressure usually goes up and down within a certain range every day. Because of this, it's best to use more than one reading to determine your
average blood pressure.
Blood pressure can also run high or low in families. It's important to look at your overall health, lifestyle, diet, and family history when comparing your number to what's considered "normal." These factors may cause you to have a higher or lower
blood pressure reading than "normal."
