What Is Hypertension?
Hypertension (high blood pressure) is an average blood pressure reading of more than 140/90. Over time, the strain this places on the heart and blood vessels can increase the risk of serious health problems, such as kidney damage, heart disease, and stroke. The first step in treating this condition involves lifestyle changes; some people may also require medication.
Blood pressure is the amount of force (pressure) that blood exerts on the walls of the blood 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.
If your blood pressure is too high, you have what's known as hypertension (also commonly referred to as high blood pressure).
Measuring Blood Pressure
To determine whether you have hypertension, it's necessary to measure your blood pressure. This is commonly done by using a device with which you are probably familiar. When taking a blood pressure reading, your healthcare provider wraps a cuff (usually made of fabric) around your arm and then slightly inflates it. The blood pressure numbers are measured by a gauge attached to the cuff. Your healthcare provider reads the numbers from the gauge as air is released from the cuff. This device 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 written as 120/80. The number on top refers to the systolic pressure. It measures the pressure inside your blood vessels at the moment your heart beats. The number on the bottom represents your diastolic pressure. It measures the pressure in your blood vessels between heartbeats, when your heart is resting.
How Is Hypertension Diagnosed?
Hypertension can only be diagnosed after taking several readings to find your average blood pressure. To find this, your blood pressure needs to be taken two or more times and each reading must be from a different day. If the average of these readings is more than 140/90, you have hypertension.
A single reading of more than 140/90 doesn't necessarily mean that you have hypertension. But your doctor will probably want to monitor your blood pressure over a period of time to see if it stays there. You can also have hypertension if the average of only one of the numbers (systolic or diastolic) is too high (see Isolated Systolic Hypertension).