Hypertension is called a silent killer?

By: John A. Sawdon Public Education & Special Projects Director

Hypertension or High Blood Pressure is often referred to as the silent killer because we usually do not experience any symptoms. Some individuals may however experience headaches, nausea and or bleeding. High Blood Pressure or Hypertension can lead to strokes or a heart attack if not treated.

Blood Pressure is the pressure or force of blood against the walls of blood vessels as it circulates throughout the body. Blood Pressure is most commonly measured against the brachial artery of the arm. This is expressed by two numbers, systolic blood pressure (the top number) is the pressure in the artery when the heart contracts. Diastolic blood pressure (the bottom number) is the pressure in the artery when the heart relaxes between beats.

  • Optimal Blood Pressure is when systolic is below 120mmHg and diastolic is below 80mmHg
  • Normal Blood Pressure is when systolic is less than 130 mmHg and diastolic blood pressure is less than 85mmHg
  • Normal High Blood Pressure is when systolic blood pressure is 130- 139mmHg and or diastolic blood pressure 85mmHg-89mmHg
  • High Blood Pressure or Hypertension is when systolic blood pressure is at or above 140 mmHg and diastolic blood pressure is at or above 90 mmHg
  • High Blood Pressure or Hypertension for individuals with Diabetes or chronic kidney disease is when systolic is at or above 130mmHg and diastolic is at or above 80 mmHg (1)

When there is no identifiable cause for high blood pressure it is called primary hypertension. This means that hypertension tends to develop gradually over the years. When there is an underlying condition that causes the high blood pressure this is referred to as secondary hypertension. Some of the conditions which cause this include;

  • Obstructive sleep Apnea
  • Kidney Problems
  • Adrenal gland tumours
  • Thyroid Problems
  • Congenital defects within blood vessels
  • Certain medications ( birth control pills, cold remedies, pain relievers, some prescription medications)
  • Illegal drugs including cocaine, amphetamines
  • Alcohol abuse including chronic alcoholism (2)

Uncontrolled Hypertension or High Blood Pressure can lead to (3):

  • Heart Attack or Stroke: high blood pressure can cause hardening and thickening of the arteries (atherosclerosis)
  • Aneurism: increased blood pressure can cause your blood vessels to weaken and bulge, forming an aneurism, if this ruptures it is life threatening
  • Heart Failure: high blood pressure causes your heart muscle to work harder which thickens the muscle. Eventually the thickened muscle has hard time pumping enough blood for your body which can lead to heart failure
  • Weakened and Narrowed Blood Vessels in Your Kidneys: when the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually the stretching scars and weakens blood vessels in the kidneys. If kidney blood vessels are damaged, they may stop removing wastes and extra fluids from the body. Extra fluid in the blood vessels may raise blood pressure even more, creating a dangerous and repetitive cycle. High Blood Pressure is the second leading cause of kidney failure behind Diabetes.
  • Thickened, narrowed or torn blood vessels in the eyes: Similar to the process mentioned in kidney failure the same process occurs in the blood vessels within the eye. This can then result in vision loss.
  • Metabolic Syndrome: this syndrome is a cluster of disorders of the body’s metabolism, including increased waist size, high triglycerides, low HDL-C lipoproteins, high blood pressure and high insulin levels. These conditions lead to diabetes, heart attack, or stroke
  • Impaired Memory & Comprehension: High blood pressure leads to difficulties with memory, comprehension and learning

Uncontrolled elevation of High Blood Pressure or hypertension can lead to a variety of changes in the myocardial structure, coronary circulation and conduction systems of the heart. These changes can lead to left ventricular hypertrophy LVD (overworking of the heart muscle which causes it to thicken), coronary heart disease (CAD), various conduction system diseases (heart beats), and systolic and diastolic dysfunction of the myocardium (middle muscle of the heart). These complications are then expressed as angina or a heart attack (myocardial infarction), cardiac arrhythmias (atrial fibrillation) and congestive heart failure. (3)

Prevalence Rates of Hypertension or High Blood Pressure:

  • 22% of Canadians between the ages of 20 and 79 have been diagnosed with Hypertension
  • 2013 was the first time high Blood Pressure rates were higher for males than females between ages of 12 and 54 years
  • 32.6% of Canadians aged 18 and over who were obese had high blood pressure (4)
  • 16% of Canadian adults with measured hypertension were unaware of their condition and another 17% were either not treated or did not have their blood pressure under control
  • 30% of South Asians and 31% of Blacks in Canada have hypertension which is the highest rates in Canada. Blacks are also more likely to develop high blood pressure at an earlier age than other ethnic groups. (5)
  • The lifetime risk for developing hypertension between the ages of 55 years to 65 years is 90% (6)

Risk Factors for High Blood Pressure or

  • Family History: if high blood pressure runs in your family then your risk is elevated
  • Advanced Age: as we age our Blood Pressure rises, this occurs through hardening of the arteries
  • Gender related risk: a higher percentage of men have blood pressure until age 45. from here to 65 years of age the rates are pretty much the same. After 65 women have a higher percentage of high blood pressure
  • Lack of Physical Exercise: Inactivity increases risk of obesity which is directly linked to higher blood pressure and heart disease.
  • Poor Diet with high levels of salt: a diet high in calories, sugars, fats, and low in nutrients contributes to poor health
  • Overweight and Obesity: a body mass index between 25 and 29 is considered overweight; a body mass index over 30 is obese. Excess weight increases the strain on the heart, raises blood cholesterol and triglyceride levels, and lowers HDL the good cholesterol. Losing as little as 10 to 20 lbs can lower you blood pressure.
  • Drinking too much alcohol: individuals should limit consumption to two drinks per day for men and one drink for women.
  • Smoking: temporarily raises blood pressure and increases risk of damage to arteries.
  • Sleep apnea: is a risk factor for high blood pressure, heart failure, heart attack and stroke

Taking Control of Your Blood Pressure

  • Be Physically Active: for 30 to 60 minutes a day. Try walking, bicycling, swimming, urban poling and or cross country skiing
  • Adjust your diet to the Dash Diet which means Dietary approaches to stop hypertension. Dash diet includes reduced salt to 2300 milligrams a day, it includes 6 to 8 servings a day of whole grains, 4 to 5 servings of fruits, 4 to 5 servings of vegetables, 2 to 3 servings of low fat dairy, 6 servings of fish, poultry, nuts, seeds. It is low in saturated fats, cholesterol and total fat.
  • Eat less sodium
  • Limit alcohol to one a day for women and two drinks a day for men.
  • Manage your weight: if your overweight losing ten lbs will lower blood pressure.
  • Do not smoke: stopping smoking reduces risk of dying
  • Reduce stress; reduction of stress will lower blood pressure


  1. Public Health Agency of Canada- Hypertension http://www.phac-aspc.gc.ca/cd-mc/cvd-mcv/hypertension-eng.php
  2. Mayo Clinic Diseases and Conditions High Blood Pressure (Hypertension) http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/basics/definition/con-20019580
  3. Mayo Clinic Diseases and Conditions High Blood Pressure (Hypertension) http://www.mayoclinic.org/diseases-conditions/high-blood-pressure/basics/definition/con-20019580.
  4. Statistics Canada Blood Pressure of Adults 2012/2013 http://www.statcan.gc.ca/pub/82-625-x/2014001/article/14101-eng.htm
  5. Heart and Stroke Foundation Press releases; High Blood Pressure Rates still Very High, Particularly for Some Ethnic Groups http://www.heartandstroke.com/site/apps/nlnet/content2.aspx?c=ikIQLcMWJtE&b=3485
  6. Public Health Agency of Canada; Hypertension. http://www.phac-aspc.gc.ca/cd-mc/cvd-mcv/hypertension-eng.php
  7. Kidney Damage and High Blood Pressure http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/WhyBloodPressureMatters/Kidney-Damage-and-High-Blood-Pressure_UCM_301825_Article.jsp#.V7NR3pMrIUF
  8. CDC Center for Disease Control and Prevention, Morbidity and Mortality Weekly Report; Prevalence of Hypertension and Controlled Hypertension ----United States 2005-2008 http://www.cdc.gov/mmwr/preview/mmwrhtml/su6001a21.htm

The articles, on the Cardiac Health Foundation of Canada website, are presented with the understanding that the Foundation is providing information only and not rendering medical advice. Please check with your family physician, specialist or health care professional before implementing any of the ideas expressed in these articles.