High Blood Pressure

(Hypertension)

The Facts

Heart disease is one of the leading causes of death worldwide, and people who have abnormally high pressure in their arteries are far more likely than others to die prematurely of heart disease.

Your arteries carry the blood from your heart throughout your body. Blood pressure is the measure of how hard your blood is pushing against the inside of your arteries. Although a certain amount of pressure is needed to carry blood through your body, if that pressure is too great, you have high blood pressure, or hypertension.

When blood pressure is measured, there are two numbers for each reading: for example, "120 over 80" is written as 120/80. This is because each heartbeat sends a pressure wave through the bloodstream. The higher number (systolic blood pressure) is the peak of the wave, when your heart contracts (the loud "thump" when you listen to your heartbeat). The lower number (diastolic blood pressure) is the lower "dip" or trough of the wave, when your heart relaxes.

Blood pressure is always recorded as the systolic number over the diastolic number, and the numbers indicate pressure as measured in millimetres of mercury on the gauge (mm Hg). In general, someone has high blood pressure if several measurements of blood pressure at the doctor's office show readings of 140 systolic or 90 diastolic or higher.

Hypertension is one of the main risk factors for heart disease, stroke, and kidney failure. In Canada, it has been estimated that around 6 million adults, almost one-fifth of the population, have high blood pressure. Many are not aware of the problem. Approximately one-third of people with hypertension do not receive adequate treatment to control their blood pressure.

The Causes

Primary (or essential) hypertension is when the cause is unknown. The majority of hypertension cases are primary. When there is an underlying problem such as kidney disease or hormonal disorders that can cause hypertension, it is called secondary hypertension. When it is possible to correct the underlying cause, high blood pressure usually improves and may even return to normal.

Other factors that can contribute to hypertension include:

age (blood pressure usually increases with age)
diet
excessive alcohol consumption
lack of exercise
obesity
sleep apnea
stress

Symptoms And Complications

Hypertension can occasionally cause headaches, vision problems, dizziness, or shortness of breath, but most people with hypertension have no symptoms. This is why hypertension is referred to as the "silent killer." Hypertension is usually discovered at a regular medical checkup when a doctor or nurse takes a blood pressure reading.

Making A Diagnosis

If your blood pressure is above the normal range for multiple readings (taken at different visits), your doctor will likely diagnose you with high blood pressure. Sometimes the doctor may diagnose you after a fewer number of readings, depending on how high above normal your blood pressure is and if you have other medical conditions. Blood pressure tends to be at its highest during exercise, physical work, or stress, and lowest during sleep. Everyone can have a temporary increase in blood pressure at one time or another, which is why it's important to take multiple readings.

If blood pressure is high, a physician will also want to know if there are any other risk factors such as high cholesterol, diabetes, inactivity, obesity, smoking, or a family history of heart disease.

The more risk factors someone has, the higher the chance of getting heart disease or a stroke.

A doctor might take an electrocardiogram (ECG) for a reading of the electric activity of the heart, or get blood samples to see if high blood pressure has caused any organ damage.

Treatment And Prevention

The management of hypertension includes lifestyle changes and the use of medications. Proper treatment of high blood pressure can add years to a person's life. Controlling blood pressure with medications can decrease the risk of stroke and heart disease.

Medications used to lower blood pressure include diuretics (e.g., hydrochlorothiazide*, furosemide, or spironolactone), beta-blockers (e.g., atenolol, metoprolol), ACE inhibitors (e.g., ramipril, enalapril, lisinopril), calcium channel blockers (e.g., nifedipine, amlodipine), angiotensin II receptor blockers (e.g., losartan, valsartan), direct renin inhibitors (e.g., aliskiren), or when the blood pressure is excessively high, direct vasodilators (e. g., hydralazine).

People who have other risk factors, especially those who have diabetes or have already suffered heart damage, may be started on medications even if their blood pressure is below "official" hypertensive levels.

In most cases, the goal of treatment is to bring down the systolic pressure to less than 140 mm Hg and the diastolic pressure to less than 90 mm Hg. For people with diabetes, target blood pressure goals are lower (e.g., less than 130/80 mm Hg). For some people are who at high risk of cardiovascular complications such as stroke or heart attack, your doctor may recommend a systolic pressure target of less than 120 mm Hg. Your doctor will determine the most appropriate goal for you.

To prevent hypertension and heart disease, here are some healthy lifestyle tips:

limit your alcohol intake to:
- no more than 2 drinks per day (or no more than 3 drinks on special occasions) to a maximum of 10 drinks per week for women
- no more than 3 drinks per day (or no more than 4 drinks on special occasions) to a maximum of 15 drinks per week for men
cut down on your salt consumption (less than 2000 mg per day from all sources)
eat more fruits, vegetables, grains, and fibre
get regular physical activity – at least 150 minutes (2 and a half hours) of physical activity per week in sessions of at least 10 minutes
lose weight (attain a healthy BMI [body mass index])
stop smoking
get more potassium in your diet (talk to your doctor first to make sure you are not at risk of hyperkalemia [higher-than-normal potassium levels in your blood])

It is important for people to know their blood pressure in mm Hg and the importance of keeping it controlled. The evidence suggests that even a small increase in blood pressure can cause a significant change in life expectancy.