Ask Your Family Doctor

Developed by the College of Family Physicians of Canada

What is high blood pressure?

Imagine that your arteries are pipes that carry blood from your heart to the rest of your body. High blood pressure (hypertension) occurs when your blood moves through your arteries at a higher pressure than normal.

High blood pressure that can be linked to a specific cause, such as a disease or drug, is called secondary hypertension. But most often the exact cause isn't known. When the cause isn't known, the high blood pressure is called essential hypertension. Your blood pressure changes often during the day depending on many factors. Therefore, your blood pressure may need to be taken several times in a quiet setting, while you are comfortable, in order to assess your blood pressure better. Doctors need to assess if you have high blood pressure to prevent heart disease and stroke. You should have your blood pressure taken once every year or two by your doctor.

What do the numbers for blood pressure mean?

Blood pressure is really two numbers written with a slash, such as 120/80. You may also hear someone say a blood pressure is "120 over 80."

The first number is the systolic blood pressure. This is the peak blood pressure when your heart is squeezing blood out. The second number is the diastolic blood pressure. It's the pressure when your heart is filling with blood - relaxing between beats. A normal blood pressure is less than 120/80. High blood pressure is when your blood pressure is 140/90 or higher.

A healthy adult with a blood pressure of less than 120 over 80 is at less risk for getting some health problems over the long run. A blood pressure reading of more than 140 over 90 (or 160 over 90 if you are over the age of 65) will need to come down to safer levels. New goals for best blood pressure readings vary by your health status. The current target values for the following conditions are :

• Diabetes – less than 130/80
• Diabetes with protein in your urine greater than 1g per day – less than 125/75
• Isolated systolic hypertension – less than 140 systolic
• Diastolic hypertension with or without systolic hypertension – less than 140/90
• Renal disease – less than 130/80

How is high blood pressure diagnosed?

Blood pressure is measured by putting a blood pressure cuff around your arm, inflating the cuff and listening for the flow of blood. Your doctor will measure your blood pressure at more than one visit to see if you have high blood pressure. The number of visits at which your doctor will measure your blood pressure before making a diagnosis depends on how high the value is and any symptoms you have.

If your blood pressure is high on more than two occasions, you probably have high blood pressure.

How often should I have my blood pressure checked?

Even in childhood, blood pressure should be checked occasionally, beginning at about age two. Have your blood pressure checked at least once every two years after age 18.
If you take medicine for high blood pressure, your doctor will check your blood pressure at each visit to make sure the medicine is working well. Ask your family doctor how often your blood pressure should be checked.

Why is high blood pressure bad?

People with high blood pressure may develop early damage to their blood vessels and their heart. This increases their risk for strokes, kidney problems and heart disease.

Does it have any symptoms?

Not usually. This is why it's so important to have your blood pressure measured regularly.

How is it treated?

Treatment begins with changes you can make in your lifestyle to help lower your blood pressure and reduce your risk of heart disease (see the box below). These things alone may work. If these changes don't work, you may also need to take medicine.

Lifestyle changes

• Don't smoke cigarettes or use any tobacco product.
• Lose weight if you're overweight (BMI >/ 25)
• Moderate intensity exercise 30 to 60 minutes, 4 to 7 days per week
• Limit how much sodium you eat.
• Limit how much alcohol you drink.
• Eat foods containing enough potassium, calcium and magnesium.
• Avoid fat and cholesterol.
• Try relaxation techniques

Even if you need medicine to control your blood pressure, making some changes in your lifestyle can help lower how much medicine you must take to control it and help reduce your risk of heart disease. High blood pressure increases your risk of heart problems, so watching any other risk factors for heart disease can help your health.

How do tobacco products affect blood pressure?

The nicotine in cigarettes and other tobacco products makes your body release adrenaline. Adrenaline causes your blood vessels to constrict and your heart to beat faster, which raises your blood pressure. If you quit smoking or using other tobacco products, you can significantly lower your risk of heart disease and heart attack, as well as help lower your blood pressure.

What about losing weight and exercising?

Losing weight if you're overweight helps lower blood pressure in most people. Losing 1 kg leads to a 1.6 reduction in systolic pressure and 1.1 reduction in diastolic pressure. Regular exercise is a good way to lose weight. It lowers high blood pressure and helps you lose weight. A study found that regular aerobic exercise decreased systolic pressure by 3.84 mmHg and diastolic pressure by 2.58 mmHg in inactive adults over 2 weeks.

Is sodium really off limits?

Not everyone is affected by sodium (salt), but sodium can increase blood pressure in some people. Most people who have high blood pressure should limit their daily sodium intake to less than 1.5g.

While some foods such as potato chips and cured meats like ham contain a lot of sodium, you may not know how much sodium is in foods like bread and cultured dairy products, such as cheese. Read labels! Don't add salt to your food. And remember that using a diuretic (pill that helps your body get rid of fluids) doesn't reduce your need to cut back on sodium.

Do I need to quit drinking alcohol altogether?

In some people, alcohol causes blood pressure to rise quite a lot. In other people, it doesn't. Limit your weekly alcohol intake to fewer than 14 standard drinks for men and 9 for women. A standard drink is 43ml or 1.5 oz of spirits (40% alcohol), 341ml or 12 oz of beer (5% alcohol), or 142 ml or 5 oz of wine (12% alcohol). If you drink alcohol, talk to your doctor.

What other things do I need to do about diet?

The Dietary Approaches to Stop Hypertension (DASH) eating plan is recommended. It is rich in whole grains, fruits and vegetables, calcium, magnesium, potassium, low in salt, sugar and fat, and is consistent with Canada’s Food Guide to Healthy Eating. It has been shown to be as effective as medicines in reducing blood pressure. The DASH diet can reduce blood pressure by 11.4/5.5 mmHg in people with high blood pressure. The DASH diet plan is available at  www.nhlbi.nih.gov/health/public/heart/hbp/dash

Increasing how much potassium you eat may help lower your blood pressure, as may increasing the amount of calcium and magnesium in your diet. Talk to your family doctor about whether these changes would be good for you to make.

Potassium can be found in potatoes, bananas, squash, spinach, bran cereal, tomatoes, prunes, raisins, cantaloupe, apricots and navy beans. Magnesium can be found in green vegetables, nuts, whole grains and shellfish. Good sources of calcium include dairy products (such as milk and cheese), greens and salmon.

Does stress affect my blood pressure?

Stress probably affects blood pressure. To help combat the effect of stress, try relaxation techniques or biofeedback. They work best when used at least once a day. Ask your family doctor for advice.

What about medicine?

There are many types of medicine used to treat high blood pressure. These are called antihypertensive medicines. Within each group of medicines, there are many different brands. The goal of treatment is to reduce your blood pressure to normal levels with medicine that's easy to take and that doesn't have side effects. This goal can almost always be met. If your blood pressure can only be controlled with medicine, you'll need to take it for the rest of your life. Don't stop taking the medicine without talking with your family doctor. If you do, you raise your risk having a stroke or heart attack.

Types of antihypertensives

• Diuretics - These drugs help your body get rid of extra sodium and fluid so that your blood vessels don't have to hold so much fluid.
• Beta blockers - These drugs block the effects of adrenaline.
• Calcium channel blockers - These drugs help prevent your blood vessels from constricting by blocking calcium from entering your cells.
• Angiotensin-converting enzyme (ACE) inhibitors - These drugs prevent your blood vessels from constricting by blocking your body from making angiotensin II. Angiotensin II is a chemical that constricts blood vessels.
• Angiotensin II Receptor antagonist - These act like ACE inhibitors, but block angiotensin from acting on your blood vessels.
• Alpha blockers - These drugs work by helping your blood vessels stay open.
• Combinations - These drugs combine two of the above medicines. Examples include an ACE inhibitor with a calcium channel blocker or a diuretic, or a beta blocker with a diuretic.

What are the possible side effects of medicine?

Different drugs have different side effects for different people. Side effects of antihypertensive drugs can include feeling dizzy when you stand up after lying down or sitting, lowered levels of potassium in your blood, problems sleeping, drowsiness, dry mouth, headaches, bloating, constipation, cough, depression and erectile problems in men.

Talk to your family doctor about any changes you notice. If one medicine doesn't work for you or causes side effects, you have other options. Let your doctor help you to find the best medicine for you.

What is Metabolic Syndrome (or Syndrome X)?

It is a condition involving the combination of risk factors for heart disease such as being overweight (or excess abdominal fat), having high cholesterol, high blood sugar and high blood pressure. Since each of these risk factors individually puts you at risk for heart disease, having 3 or more of them together increases your risk 6 times more for a heart attack or stroke. Syndrome X is the result of inactivity and a diet rich in saturated fats. It can be controlled with lifestyle changes such as healthy eating, exercise, weight loss and smoking cessation (1).

Appendix:  BMI is Body Mass Index calculated at weight in kg divided by height in meters squared (kg/m2)

Revised 2007 The College of Family Physicians of Canada

This information provides a general overview on this topic and may not apply to everyone. To find out if this information applies to you and to get more information on this subject, talk to your family doctor. This health education material has been favorably reviewed by the Patient Education Review Committee of the College of Family Physicians of Canada: Dr Cathy MacLean, Halifax, NS (Scientific Editor) Dr C. Richard Fischer, Pickering, ON Dr Patrice Laplante, Fleurimont, QC Dr Richard Moffatt, Red Deer, AB Dr David Nunn, Kentville, NS Dr Cornelius Woelk, Winkler, MB The College of Family Physicians of Canada, one of the nation's largest medical groups, is committed to promoting and maintaining high standards for family physicians - the doctors who provide ongoing, comprehensive care for people of all ages. This patient education information was developed by The College of Family Physicians of Canada in cooperation with the American Academy of Family Physicians.

Support for this program has been provided by an educational grant to the Research and Education Foundation by Scotiabank.