Blood pressure is one of the most important factors affecting cardiovascular health. High blood pressure is a serious threat to heart health: it significantly increases the risk of heart attack and stroke.
Blood pressure measures the force exerted on the walls of the arteries as blood circulates through them.
High blood pressure, or hypertension, means too much force is being exerted on the arteries. If the artery walls are stretched too much from excess pressure, they can become weak or damaged, or even rupture. The result is increased risks to heart health.
What the numbers mean
A blood pressure reading always has two numbers: the systolic and the diastolic. The first number (systolic) represents pressure on the arteries when the heart muscle contracts or beats, forcing out blood. The second number (diastolic) represents pressure on the arteries when the heart muscle relaxes to fill with blood between beats.
The letters mmHg that often appear after the numbers are an abbreviation for millimeters of mercury, which is a unit used to measure pressure.
What’s normal, what’s high
Your blood pressure varies depending on circumstances – for example, it is lower when you are asleep and higher when you are agitated. However, if your blood pressure is consistently higher than recommended, you may have hypertension.
Optimal blood pressure is under 120 systolic and 80 diastolic, according to the Public Health Agency of Canada (PHAC); but the agency defines normal blood pressure as anything lower than 130 systolic and 85 diastolic.
A diagnosis of high blood pressure, or hypertension, means blood pressure consistently over 140 systolic or 90 diastolic. PHAC classifies readings of 130 to 139 systolic and 85 to 89 diastolic as “normal-high.”
You can have high blood pressure based on either your systolic or diastolic pressure (even if the other number is within normal range), or based on both numbers.
What you can do
Many factors affect blood pressure. Some of those factors can’t be changed: genetics, for example, and age (risk of hypertension rises as we get older). But many other factors can be modified through lifestyle changes. These modifiable risk factors include being overweight or obese, having a sedentary lifestyle, smoking, and eating a high-sodium diet.
Steps you can take to help control blood pressure include:
- becoming smoke-free
- being physically active
- keeping a close eye on sodium (salt) intake
- including plenty of fruit and vegetables in your diet
- limiting saturated fats
- drinking alcohol only in moderation
This information is provided by Women’s College Hospital and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: Feb. 25, 2014