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. Plaques can also 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.

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 changes as your heart contracts and relaxes. It is measured as two numbers; one on top of the other. It is expressed in mmHg (millimeters of mercury).

The top number (systolic) represents the pressure when your heart contracts and pushes blood into your circulatory system. The bottom number (diastolic) is the pressure when the heart relaxes and fills with blood between beats.  

Blood pressure is a measurement that is not always consistent and can fluctuate frequently throughout the day. These fluctuations are due to many different factors, such as:  

• Activity and exercise  
• Emotions and mood 
• Pregnancy 
• Smoking 
• Alcohol and caffeine consumption 
• Some medications  
• Body position 

This video explains how to measure your blood pressure properly with a home monitor.  

Hypertension

Hypertension, or high blood pressure, means there is too much pressure in your blood vessels. This causes your heart to work harder and can result in damage to your blood vessels and lead to heart damage over time.

Hypertension is when consistent blood pressure readings exceed 140/90mmHG (or when readings are higher than 130/80mgHG for people with diabetes or kidney disease). A single or occasional blood pressure reading higher than 135/85 does not necessarily mean you have high blood pressure because blood pressure fluctuates frequently.

If your reading is higher than normal, your doctor may take several readings over time and/or have you monitor your blood pressure at home before diagnosing you with hypertension.  

You can have hypertension for years without knowing it. High blood pressure often has no warning signs or symptoms; however, left untreated over time increases your risk of the following health conditions:  

• Stroke  
• Heart attack 
• Heart failure 
• Dementia 
• Kidney disease  
• Eye problems (retinopathy)  
• Erectile dysfunction 

This video explains the effects of high blood pressure on the blood vessels and the heart. 

What Are the Symptoms of 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 

Hypotension

Hypotension, otherwise known as low blood pressure, is a reading of less than 90/60mmHG. 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 some of your vital organs are not receiving enough blood.   

What Are the Symptoms of 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. 

Am I at Risk For High Blood Pressure?

You are at risk for high blood pressure if:

• You are older than the age of 65.  
• 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 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. 
• You have a history of hypertensive disorder of pregnancy  

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 primary hypertension increases with age. Several lifestyle factors can increase the risk for primary hypertension, including: 

• Too much salt in the diet  
• Drinking alcohol excessively (Less is best! No more than 2 alcoholic drinks per day or 6 alcoholic drinks per week)  
• Obesity 
• Getting insufficient exercise 
• Experiencing unmanageable stress 

1. 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) 

How is Blood Pressure Diagnosed?

A healthcare professional will use a blood pressure machine and place the inflatable cuff around your arm while sitting. 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 healthcare provider will most likely diagnose you with hypertension if you have several readings of 140/90mmHG or higher. If you have readings of 130/80mmHG or higher and have diabetes or chronic kidney disease, you are likely to be diagnosed with hypertension.  

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 healthcare professional. Changing what you eat, how much you exercise and other lifestyle changes can help you prevent or control high blood pressure. Here’s what you can do, along with suggestions for getting started. 

Choose Heart Healthy Foods 

• Make sure your diet emphasizes foods high in fibre such as fruits, vegetables and whole grains. 
• Eat foods lower in fat such as low-fat dairy products and lean meat (fish, chicken and legumes). 
• Limit your salt to less than 2000mg per day. Most of our salt intake comes from processed and packaged foods. Look at the amount of sodium in these products and choose foods with less than 5% of the daily value of sodium. Do not add salt to recipes or at the table.  

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 7-12 mm Hg.⁴ 

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.⁵  

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 moderate to vigourous physical activity four to seven days a week can decrease total blood pressure by an average of 12mmHg for systolic and 6mmHg for diastolic.⁶  

Limit Your Alcohol Intake

Even if you're healthy, alcohol can raise your blood pressure. We recommend that patients with heart disease do not drink alcohol.

If you do drink, it is important to understand ways to reduce the risk of long-term impacts on your heart and overall health. Low-risk guidelines recommend no more than one to two standard drinks per week. If you drink over two drinks per week you are increasing your risk of certain cancers, heart disease, and stroke. 

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 healthcare professional at least once every two years or as often as they suggest.

If you have been told you have high-normal blood pressure, or pre-hypertension, Canadian guidelines recommend you have your blood pressure checked at least once a year. This video explains how to measure your blood pressure properly with a home monitor.  

About Lifestyle Changes

Health practitioners may first recommend lifestyle changes to lower blood pressure but like many changes, 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 moderate to vigorous exercise a day for as many as four to seven days a week. 
2. Diet: Follow the DASH diet and aim for less than 2000mg sodium each day
3. Quit Smoking: Find a program to help you quit. 

If your blood pressure is under control and you monitor it at home, you may be able to make fewer visits to your healthcare professional. If you have been prescribed medication, take it as directed. 

Medication Therapy for High Blood Pressure

Sometimes lifestyle changes are not enough. If blood pressure levels do not improve after several months of lifestyle changes, or if 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 check out the Hypertension Medication page. 

Resources

• Hypertension Canada
• Recommended Blood Pressure Devices
• Blood Pressure Record Card