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 20% of men and 19% of women 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.
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:
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.