Blood pressure changes from minute to minute and at different times of day. Hypertension is a persistent increase of blood pressure above the normal range. Anyone can develop high blood pressure, but it becomes more common as you get older. Once high blood pressure develops, it usually lasts for life (unless lifestyle changes are made). It must be controlled.
High blood pressure is one of the leading health problems in Canada. It can cause strokes, heart attacks, and heart and kidney failure. It is also related to dementia and sexual problems. Finding high blood pressure early, treating and controlling it can reduce the risk of developing these problems.
Each time your heart beats, it produces a wave of pressure. That wave of pressure is measured with two numbers, such as 124/84 mmHg. The first number is the systolic pressure when your heart contracts to pump blood. The second number is the diastolic pressure in the arteries when your heart relaxes and fills with blood. Blood pressure is measured in millimeters of mercury or mmHg.
When measured in the doctor’s office, ideal blood pressure for most people is less than 120/80 mmHg. Most people should have a blood pressure of less than 140/90 mmHg. Blood pressure that is consistently 140/90 mmHg or higher is considered hypertension. Anyone with diabetes or kidney disease should aim for a blood pressure of less than 130/80 mmHg.
Whether or not you have high blood pressure, it is important to have your blood pressure checked regularly. Eight out of 10 Canadians will develop hypertension during their lifetime. High blood pressure has no warning signs or symptoms – which is why it is often called a ‘silent killer.’
Have your blood pressure checked at least once every two years by a health care provider. Do it more often if your blood pressure is high. You can also monitor your blood pressure more often at home. If home blood pressure readings are done properly they may be more accurate than those done in the doctor’s office. Regular monitoring helps ensure that high blood pressure is diagnosed and controlled before it leads to serious health problems.
Know what your blood pressure is and remember that both numbers are important. If either the systolic or diastolic number is consistently high, you need to make changes in your lifestyle. You may need further monitoring and treatment. (Blood pressure of more than 135/85 mmHg measured at home or 140/90 mmHg measured in a doctor’s office is considered high.)
Blood pressure changes depending on your activity. When you are in pain or have been running or exercising, your blood pressure goes up. This is a normal protective response. It helps your body supply more oxygen to muscles and other parts of the body.
Some people have higher blood pressure (called white coat hypertension) when they visit the doctor’s office because they feel anxious in this setting. However, as they go about their usual daily activities they have normal blood pressure. This condition is called ‘white coat’ hypertension (referring to increased blood pressure in reaction to the white coat worn by the health care provider). There are no real factors making white coat hypertension less or more likely in a person. The key symptom is a lot of variation between readings.
If your doctor thinks you might have white coat hypertension, you may be asked to monitor your blood pressure at home or do a 24-hour ambulatory blood pressure monitor test. An ambulatory blood pressure monitor is a small machine, about the size of a portable radio. You wear it on your belt for 24 hours.
This machine can show your doctor what your blood pressure has been every 15 to 30 minutes over 24 hours. This information can help you both to see the changes in your blood pressure during a normal day. People with white coat hypertension may still have some increased risk of health problems. However, the risk is lower than in those with raised blood pressure at the doctor’s office and at home. Regular monitoring is still required, as many people with white coat hypertension will develop high blood pressure over time.
‘Masked’ hypertension is a term used to describe how some people have normal blood pressure when measured in the doctor’s office, but have high blood pressure in other situations. You may be puzzled by this term. Blood pressure varies a lot and you can have high readings at home or at work, but normal readings when seeing the doctor.
The doctor may suspect that a person has masked hypertension when there is a lot of variation between blood pressure readings. If your doctor suspects masked hypertension, you may be asked to monitor your blood pressure at home. You might also wear an ambulatory blood pressure monitor for 24 hours.
It is important to ‘unmask’ high blood pressure, since those with masked hypertension are at higher risk for heart disease and stroke. They require medication or lifestyle changes to keep blood pressure under control. Alert your doctor if you have high blood pressure readings at home, even if you have normal blood pressure in the doctor’s office.
Measuring and tracking your blood pressure regularly, and keeping a record, can be very useful. This information helps your doctor know whether you are at risk of developing high blood pressure, and how well your blood pressure is controlled. If you have been diagnosed with high blood pressure, keeping track helps you see the benefits of treatments and lifestyle changes. It also reminds you to stick to your treatment plan.
Home monitoring can help you:
Blood pressure instruments can be purchased in most pharmacies. Be sure to buy a blood pressure instrument approved by one of the following:
Labels showing the approval of these agencies will be marked clearly on the box. If you are unsure whether an instrument is approved, ask the pharmacist for help.
Ask your doctor or pharmacist to check your device from time to time, to be sure it is measuring accurately and that you are using the right size of cuff for your arm. The site www.hypertension.ca contains a list of approved devices.
When measuring your blood pressure, follow this advice:
Environmental or genetic factors, or a combination of these, can cause high blood pressure. We cannot change our age, ethnic background or gender. However, other factors are within our control, including lifestyle choices such as proper diet and exercise, stopping smoking, and managing stress*.
Lifestyle changes are an important part of a plan to lower blood pressure and reduce the risk of cardiovascular disease and stroke. Changing your lifestyle takes time and practice, but making a commitment to a healthy lifestyle is the first step!
Remember, high blood pressure is not a disease. It is a risk factor for cardiovascular disease. You can control your blood pressure, and many other risk factors, by taking greater responsibility for your health. Talk to your doctor or another health professional about your cardiovascular risk and ways to reduce it.