How does high blood pressure cause heart disease and stroke?

Over time, high blood pressure can damage blood vessel walls, causing scarring that promotes the build-up of fatty plaque. This build-up can narrow and eventually block arteries. It also strains the heart and eventually weakens it. Very high blood pressure can cause blood vessels in the brain to burst resulting in a stroke.

What you can do to control your blood pressure.

High blood pressure can be caused by many factors. You can’t control some factors, such as age, ethnicity and gender. Other factors, such as diet, exercise and smoking can be changed through lifestyle changes to reduce your risk for high blood pressure.

• Have your blood pressure checked regularly as recommended by your healthcare provider.
• If your doctor has prescribed medication, take it as directed. 
• Reduce the amount of sodium you eat. High sources of sodium are found in many types of convenience and snack foods and smoked, salted, cured or canned meats and fish. Also try to limit your use of salt in cooking and at the table. The Heart and Stroke Foundation recommends that Canadians eat less than 2,300 mg of sodium (about 1 tsp / 5 mL of salt) a day total from processed foods and salt added during food preparation and at the table. For those who have been diagnosed with high blood pressure (hypertension), or those who are salt sensitive, sodium intake should be limited to 1,500 mg (2/3 tsp) a day if you are 18 to 50 years of age, 1,300 mg if between the ages of 51 to 70, and to 1,200 mg per day if older than 70.
• Eat a healthy, balanced, diet that is lower in fat (especially saturated and trans fats) based on Canada’s Food Guide. Get healthy eating tips from our Healthy eating section. Learn more about the DASH eating plan, which can help lower your high blood pressure.
• Be physically active for at least 150 minutes per week doing moderate- to vigorous-intensity aerobic physical activity, in bouts of 10 minutes or more. Speak to your healthcare provider before starting a physical activity program.
• Achieve and maintain a healthy body weight. If you are overweight, losing even 5% to 10% of your weight can help to reduce your blood pressure as well as dramatically decrease your chances of having a stroke or heart attack.
• Be smoke-free. If you smoke, speak to your doctor or healthcare provider about quitting. If you don’t smoke, minimize exposure to second-hand smoke. 
• Limit alcohol intake to no more than one to two drinks a day, to a weekly maximum of 14 drinks for men and 9 drinks for women.*
• Find healthy ways to manage your stress. Too much stress may increase your blood pressure. Research suggests that the way in which you manage your stress is very important. Avoid unhealthy stress coping mechanisms such as smoking, alcohol use, poor food choices, not being active, watching too much television and find relief instead with physical activity, socializing, laughter and healthy eating. Remember to take time out for yourself.

* Guidelines do not apply if you have liver disease, mental illness, are taking certain medication, or have a personal or family history of alcohol abuse, are pregnant, trying to get pregnant or breastfeeding. If you are concerned about how drinking may affect your health, check with your healthcare professional.

How to measure your blood pressure at home.

Home monitoring can assist your doctor in diagnosing your blood pressure correctly. Some people have higher blood pressure when they visit the doctor’s office. However, as they go about their usual daily activities, they have normal blood pressure. This condition is called “white coat” hypertension (referring to the white coat worn by the healthcare provider). On the other hand, some people have normal blood pressure when measured in the doctor’s office, but have high blood pressure in other situations. This is known as “masked” hypertension. Your doctor may ask you to monitor your blood pressure at home if needed.

It is important to make sure that your home monitor is taking correct measurements so your healthcare provider will have an accurate overview of your blood pressure.

Before you buy a home monitor, you'll need to know your correct cuff size. To find your cuff size:

• Measure the circumference (midpoint between shoulder and elbow) of your bare upper arm.
• Match your measurement with measurements provided on the monitor’s package or instruction manual.

Accurate readings also depend on how you prepare to take your blood pressure. Follow these steps to get the most accurate reading:

• Rest for 5 minutes before measuring.
• Do not smoke or drink caffeine (coffee, tea, cola and some sports drinks) for 30 minutes beforehand.
• Do not measure your blood pressure when you are upset or in pain.
• Empty your bladder or bowel before starting, if necessary.
• Sit quietly with your feet flat on the floor and back resting against the back of a chair or a firm surface for at least 5 minutes before measuring and during measurement.
• Use the same arm each time. Remove bulky or tight clothing from your arm completely.
• Wrap the blood pressure cuff snugly around your bare upper arm (2 fingers should fit between the blood pressure cuff and your arm). The edge of the cuff must be 1 or 2 cm ( ½ an inch to an inch) above your elbow.
• Place your arm on a table or a firm surface. The cuff must be at the level of your heart.
• Do not talk or watch TV during the test.
• Take one reading and record your blood pressure.
• Bring a record of your readings to your next appointment with your healthcare provider.

Hypertension Canada educates the public on how to measure blood pressure at home. Watch the Home measurement of blood pressure video. 

How to buy a home blood pressure monitor

Your doctor or pharmacist can help you choose a monitor and select a cuff size that is right for you.  The Foundation suggests that the unit be automated instead of manual. Advise your doctor or pharmacist if you have an irregular heart rhythm as some devices may not be advised for individuals with an irregular heartbeat. The Foundation further recommends that you select a device recommended by Hypertension Canada. 

Recommended by Hypertension Canada (www.hypertension.ca).

Look for this logo or ask a healthcare provider to help you choose the right home blood pressure monitor.

Once you have purchased a home monitor, take it to your healthcare provider’s office once or twice a year to make sure it continues to give accurate readings.

Hypertension Canada publishes Public Recommendations based on the Canadian Hypertension Education Program (CHEP) guidelines for health professionals. Learn more about the Public Recommendations and other useful resources.

For more information on blood pressure, please read our brochure Get Your Blood Pressure Under Control. You may also wish to use the Blood Pressure Wallet Card to keep track of your blood pressure readings.

Last modified: September 2011
Last reviewed: May 2011