by Habibat Aziz Garuba, MD, FRCPC
What is hypertension/high blood pressure?
Hypertension is the medical term for high blood pressure above a certain threshold. Blood pressure (BP) is the force of blood flow against the walls of our arteries (the blood vessels that carry blood away from the heart and distribute it to the rest of the body).
Blood pressure has two components: systolic pressure, (the top number) is the pressure when the heart beats, and diastolic pressure (the bottom number) is the pressure when the heart relaxes. Normal blood pressure is usually less than 120/80. “Pre-hypertension” is when the top number is between 120-139 and the bottom number is between 80-89 (although certain resources may call this Stage I hypertension). In Canada, hypertension is usually diagnosed when a person’s blood pressure is consistently above 140/90 (for patients with diabetes, hypertension is a blood pressure consistently above 130/80).
Hypertension can be diagnosed by repeated measurements of blood pressure in a doctor’s office or by using a special blood pressure monitor at home. Blood pressure fluctuates throughout the day and depends on your level of physical activity (it usually rises with exercise). Some people may have “white coat syndrome” where BP is high in the doctor’s office because they are anxious or stressed however it is normal at home in an environment that is not stressful. Accurate measurements are necessary to determine if a person truly has high blood pressure. It is important to know your number. If your blood pressure is high, you need to seek medical attention.
What causes hypertension? Am I at risk?
The exact cause of “essential” or “benign” hypertension (i.e. high blood pressure that is not caused by another disease or medical condition) is unknown. However, there are many factors that can increase a person’s risk of developing hypertension such as:
- Increasing age
- Sedentary lifestyle
- Poor diet, high in salt and fat
- Alcohol consumption
- Family history of high blood pressure
- Being overweight or obese
- Having diabetes
Blacks have a higher prevalence of hypertension than most other racial/ethnic groups and tend to develop hypertension at a much younger age. Blacks are also more likely to develop complications associated with hypertension (see below). Research shows that Blacks are more sensitive to salt (which increases blood pressure) and that certain high blood pressure medications are less effective in Blacks compared to other racial/ethnic groups.
What are the consequences of having hypertension?
High blood pressure that is uncontrolled or frequent surges of high blood pressure can increase the risk of damage to vital organs and can cause death. Uncontrolled hypertension can lead to:
- Stroke (either a bleed or a clot in the brain that damages brain tissue)
- Heart attack
- Kidney failure
- Eye damage and vision loss
- Erectile dysfunction
- Rupture or tear of major arteries
How is hypertension treated?
Hypertension is treated with a combination of two strategies: first, changing lifestyle habits that may contribute to elevated blood pressure; and second, taking prescribed medication (anti-hypertensives) to lower blood pressure. Important changes that can help reduce the risk of hypertension and its complications include:
- Exercise and weight loss – research shows that each 10kg decrease in weight can lower systolic blood pressure by 5-20 points. Maintaining a healthy weight and engaging in regular exercise (30 – 60 mins of aerobic activity at a moderate intensity at least 4-7days per week) is beneficial.
- Cutting back on salt/sodium – use less than 5 grams of table salt per day (or less than 2000 mg of “sodium” which is one of the chemical components of salt). Beware of canned or packaged foods and always read nutritional labels to see how much sodium is contained.
- Eat a healthy diet – Canadian guidelines recommend the “DASH” diet (Dietary Approaches to Stop Hypertension) which includes a diet high in fruits, vegetables, low-fat dairy products, whole grain foods rich in dietary fibre, and protein from plant sources. Avoid foods high in saturated fat and bad cholesterol.
- Limit alcohol consumption – avoid drinking more than 14 drinks per week (for men) or 9 drinks per week (for women). A “standard drink” is considered to be: 44ml of 40% spirits, 355ml of 5% beer, and 148ml of 12% wine.
- Avoid/quit smoking – many resources are available to help quit smoking including counselling, medication (nicotine replacement therapies) and group therapies. A useful resource is https://myquit.ca. Here in Ottawa, the University of Ottawa Heart Institute has a Quit Smoking Program that can help those who are interested in learning more (link below) or starting the journey towards smoking cessation.
- Stress management – stressful situations may contribute to worsening control of blood pressure. Relaxation therapies and counselling are options to help reduce daily stress levels.
- Taking medication as prescribed – once blood pressure numbers become normal, it is important to keep taking medication as prescribed by your doctor otherwise, blood pressure may rise again. Remember that hypertension is not “cured” because the blood pressure numbers are lower, only maintained. Discuss with your doctor if there are certain circumstances where medications may need to be temporarily withheld (e.g. for certain surgeries or procedures). Note that certain medications for blood pressure may be less effective in Blacks than other ethnic groups, therefore it is important to work with your physician to ensure that you are on the right medication for you.
Where can I find more information?
Your physician is the best resource to assess whether or not you have high blood pressure. The following resources provide more general information:
University of Ottawa Heart Institute Prevention & Wellness Centre
University of Ottawa Heart Institute Quit Smoking Program
WebMd: High Blood Pressure in African Americans
THE CHECK-UP is a column aimed at increasing awareness and providing general information on selected health topics that are prevalent in people of African and Caribbean descent. The information presented is not exhaustive and does NOT represent personalized medical advice nor does it replace an individualized assessment and treatment by a physician or other medical professional. Please contact your doctor or seek medical attention if you have any concerns about your health or any matters referenced in this article.
About the writer
Dr. Habibat A. Garuba is currently a Resident Physician at the University of Ottawa Heart Institute completing her specialization in Cardiology. She is a Fellow of the Royal College of Physicians of Canada, licensed in the specialty of in Internal Medicine. She also holds a Bachelor of Science degree in Pharmacy from the University of Toronto. Her areas of interest include clinical cardiology, echocardiography (cardiac ultrasound), heart failure, global health, and pharmaceutical policy.