Blood Pressure


What Is Blood Pressure?

Do you sense your blood moving through your body? It may be barely noticeable when you’re resting, pumping harder when you walk, run or climb the stairs. As blood circulates, it exerts pressure against the walls of your arteries. That’s blood pressure, a normal part of the body’s system of delivering nutrients to its many organs.

Blood pressure is determined by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure.

High blood pressure, also known as hypertension, makes your heart work a lot harder and causes excess force on your artery walls. This can scar the walls and trigger the buildup of plaque, which narrows the arteries and causes a type of cardiovascular disease (CVD) called coronary artery disease. A narrowing artery can become completely blocked, leading to a heart attack. Also, plaques can break away from the artery wall and cause a blockage elsewhere.

High blood pressure is strongly linked to heart disease. In fact, “high blood pressure is the leading risk for death throughout the world.”7  It has been called the silent killer because it often has no warning signs or symptoms. You could have high blood pressure for years without knowing it, putting you at greater risk for cardiovascular disease and organ damage.

Which is what makes it even more alarming that between 2000 and 2005, the prevalence of high blood pressure among Canadians rose more than 20%2. In the Champlain region of Ontario, almost 15% of residents have been diagnosed with high blood pressure.6 Canadian adults diagnosed with high blood pressure are six times more likely to be diagnosed with diabetes than those with healthy blood pressure values.9

It’s important to pay attention to your blood pressure. Begin by learning your own blood pressure levels and what you can do to improve it.

How is Blood Pressure Measured?

Your blood pressure is measured as two numbers. The first shows your heart at work, when it is exerting pressure to fill your arteries with blood. The second represents your heart at rest, filling with blood between beats. These are called the systolic and diastolic values, respectively.

For example, a blood pressure rate of 124/85 mm Hg, as shown in the graphic. The top number is the systolic rate and the bottom the diastolic. They are both measured in millimeters of mercury (mm Hg).

This video lecture explains systolic and diastolic pressure (Khan Academy). 

Your doctor or other medical practitioners have likely checked your blood pressure before. He or she would have wrapped an inflatable cuff around your upper arm and used a stethoscope to record both the systolic and diastolic pressures.

Healthy Blood Pressure

Normal blood pressure is a reading of lower than 120/80, meaning your heart is pumping at 120 mm HG and resting at 80 mm HG. When your blood pressure numbers are consistently greater than 140/90, you’re considered to have high blood pressure, or hypertension. If you have diabetes or kidney disease, 130/80 is considered a high reading.


Hypertension, or high blood pressure, is when consistent measures exceed 140/90 (or readings higher than 130/80 for people with diabetes or kidney disease). You should make significant lifestyle changes, including medication, to reduce your risk of developing heart disease. This video lecture explains the effects of hypertension of blood vessels (Khan Academy). 


Pre-hypertension indicates you have slightly surpassed the ideal target values and are at increased risk of developing high blood pressure, which may require medical therapy. If your systolic blood pressure is between 120 and 139 and/or your diastolic is between 80 and 89, you should take the necessary steps to decrease your blood pressure.


Hypotension, otherwise known as low blood pressure, is a reading of less than 90/60. It can be just as serious and dangerous as high blood pressure, as it may indicate that the force of your blood flow is inadequate. This could mean certain of your vital organs are not revieving enough blood.  


Am I at Risk For High Blood Pressure?

You are at risk for high blood pressue if:

  • You are older than the age of 65: about 50% of people older than 65 have high blood pressure
  • You have relatives with high blood pressure
  • You are of African, South Asian or First Nations heritage, where high blood pressure is more common
  • You are male, or a female past menopause: Men are more likely to develop high blood pressure than women, but the risk for women increases after menopause, putting them in even greater jeopardy than men.

What Causes High Blood Pressure?

There are two main causes, or types, of high blood pressure:

  1. Primary (also known as “essential”): Cases in which there is no easily identifiable cause for high blood pressure. The risk of developing essential hypertension increases with age. A number of lifestyle factors can increase the risk for essential hypertension, including:
    • Getting too much salt in the diet
    • Drinking alcohol excessively (males no more than two drinks a day; females one drink a day)
    • Being overweight
    • Getting insufficient exercise
    • Experiencing unmanageable stress
  2. Secondary: Cases in which high blood pressure does have an identifiable cause. Common causes of secondary hypertension include:
    • Kidney disease
    • Hormone disorders
    • Some drugs (such as birth control pills and nonsteroidal anti-inflammatory drugs)
    • Sleep apnea (repeated, short stops in breathing while sleeping)
    • Arteriosclerosis (hardening of the arteries)

This video lecture explains hypertension symptoms and categories (Khan Academy).

What Are the Symptoms?

High Blood Pressure (Hypertension)

High blood pressure has been called the silent killer because it often has no warning signs or symptoms. You could have high blood pressure for years without knowing it, putting you at greater risk for cardiovascular disease and organ damage.

If damage has occurred, you may have symptoms that include:

  • Headache
  • Shortness of breath
  • Tiredness
  • Nausea
  • Vomiting

Low Blood Pressure (Hypotension)

People who take certain high blood pressure medications, such as diuretics, have an increased risk for low blood pressure.
Low blood pressure can be considered “normal pressure” to some people who have low blood pressure all the time. In this case, they have no signs or symptoms.

Symptoms of hypotension may include:

  • Dizziness
  • Fainting
  • Cold and sweaty or clammy skin
  • Tiredness
  • Blurry vision
  • Nausea

Hypotension is a medical concern only if it causes signs or symptoms or is linked to a serious condition, such as heart disease.

How is Blood Pressure Diagnosed?

Your doctor will use a blood pressure machine, placing the inflatable cuff around your arm while you are seated. It takes less than five minutes. If your blood pressure readings are high, your doctor may ask that you return for additional measurements on different days because blood pressure can vary widely from day to day.

Your doctor will most likely diagnose you with high blood pressure if you have several readings of 140/90 or higher. If you have readings of 130/80 or higher and are diabetic or have chronic kidney disease, you are likely to be diagnosed with high blood pressure. 


What Can I Do If I Am Diagnosed With High Blood Pressure?

You can lower your blood pressure by changing some aspects of your lifestyle and, if necessary, taking medication prescribed by a properly trained health care professional. Changing what you eat, how much you exercise and other ways you live your life can help you prevent or control high blood pressure. Here’s what you can do, along with suggestions for getting started.

Eat Healthy Food

Make sure your diet emphasizes fruits, vegetables, whole grains and low-fat dairy foods. An easy tool for planning healthy meals is the Dietary Approaches to Stop Hypertension (DASH) diet, which can help you reduce your systolic blood pressure by 8-14 mm Hg. 

Get plenty of potassium, which can help prevent and control high blood pressure, and pay attention to the amount of salt that's in the processed foods you eat, such as canned soups or frozen dinners.

Achieve and Maintain a Healthy Weight

If you're overweight, a modest reduction in weight of 10% of your current body weight can lower your blood pressure. For every kilogram of weight loss, you can reduce your blood pressure by 1.1/0.9 mm Hg.

Be More Active

Regular physical activity can help lower your blood pressure and keep your weight under control. Aiming for 30 to 60 minutes of physical activity four to seven days a week can decrease total blood pressure by 4.9/3.7 mm Hg.

Limit Your Alcohol Intake

Even if you're healthy, alcohol can raise your blood pressure. If you choose to drink alcohol, do so in moderation — one to two drinks per day for a weekly maximum of nine for women and 14 for men. Limiting your alcohol could decrease your systolic blood pressure by 2-4 mm Hg.

Stop smoking

Smoking leads to injured blood vessel walls and speeds up the process of hardening of the arteries. If you smoke and want to quit, visit our section about Smoking.

Manage Stress

Set aside some time every day to relax. Practice healthy coping techniques, such as muscle relaxation and deep breathing. Getting plenty of sleep can help too.

Monitor Your Blood Pressure

Have your blood pressure checked regularly. High blood pressure often has no symptoms, so have yours checked by a health care professional at least once every two years or as often as your doctor suggests. If you have been told you have high-normal blood pressure, or pre-hypertension, Canadian guidelines recommend that you have your blood pressure checked at least once a year. This detailed video provides correct guidelines for measuring your blood pressure at home (Hypertension Canada).

About Lifestyle Changes

Doctors often first try to lower a patient’s blood pressure by having the patient make lifestyle changes, but like most change, it can be hard. If you had to focus on just three, the most important ones would be:

  1. Physical Activity: Get 30 to 60 minutes of exercise a day for as many as four to seven days a week
  2. Diet: Follow the DASH diet and aim for less than 2,300 mg sodium each day
  3. Quit Smoking: Find a program to help you quit

If your blood pressure is under control, you may be able to make fewer visits to your doctor if you monitor your blood pressure at home. If your doctor has prescribed medication, take it as directed.

Medication Therapy for High Blood Pressure

But sometimes lifestyle changes are not enough. If blood pressure levels do not diminish after several months of lifestyle changes, or when very high blood pressure poses an immediate threat to health, medication may be necessary, particularly for those with organ damage, chronic kidney disease or diabetes.

Most people who are on blood pressure medication require at least two different drugs in addition to lifestyle changes to properly treat their condition.


To learn more about the many treatment options for lowering high blood pressure on our Hypertension Medication page.

More detailed information about the diagnosis and treatment of high blood pressure is available from Hypertension Canada.


  1. Health Canada, Healthy Canadians: A Federal Report on Comparable Health Indicators in Health Care System, 2010.
  2. Tu, K., Lipscombe LL., Chen. Z., (Canadian Hyperteion Education Program Taskforce). Prevalence and incidence of hypertension from 1995 to 2005: a population-based study. Canadian Journal of Medicine. 2008 (178): 11.
  3. Statistics Canada, High blood pressure, by sex, and by province and territory (percent) 2007-2011, 2012.
  4. Wilkins K, Campbell N, Joffres M, et al. Blood pressure in Canadian adults. Statistics Canada, 2010. No. 82-003-X.
  5. Robitaille C, Dai S, Waters C, et al. Diagnosed hypertension in Canada: incidence, prevalence, and associated mortality. CMAJ. 2012 (184): E49-E56.
  6. Health Canada. Canadian Community Health Survey
  7. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension. 2003 (42):1206-1252.
  8. Canadian Hypertension Education Program (CHEP)  
  9. Strategy, N.D.S., Report from the Canadian Chronic Disease Surveillance System: Hypertension in Canada 2010. Public Health Agency of Canada, 2010.
  10. European guidelines on cardiovascular disease in clinical practice: executive summary. European Journal of Cardiovascular Prevention and Rehabilitation. 2007 14 (Suppl 2): E1-E40.