Blood Pressure


Blood pressure is the result of circulating blood exerting pressure against the walls of your arteries. This pressure is very important because it allows the blood to flow through the arteries and deliver nutrients to all the organs of your body. 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 more narrow your arteries, the higher your blood pressure.

Your blood pressure is recorded as two numbers (for example, 124/85 mm Hg, as shown in the graphic). The top number is the systolic and the bottom the diastolic. These values are measured in millimeters of mercury (mm Hg).

  • The systolic value represents your heart “at work,” the pressure exerted when your heart beats and fills your arteries with blood.
  • The diastolic value represents your heart “at rest,” between beats. During this phase, your heart fills with blood in advance of the next beat.
Optimal blood pressure is a reading of lower than 120/80. When your blood pressure numbers are consistently greater than 135/85, you’re considered to have high blood pressure, or hypertension (but if you have diabetes or kidney disease, 130/80 is considered a high reading).

In addition to your normal, or “ideal,” blood pressure values, there are three categories of blood pressure — hypertension, pre-hypertension, and hypotension — each of which has a different impact on your health. 


Hypertension, or high blood pressure, is present when there are consistent measures that exceed 135/85 (or readings higher than 130/80 for people with diabetes or kidney disease). This indicates that to reduce your risk of developing a serious condition, like heart disease, you should make significant lifestyle changes, including even medication, to lower your blood pressure.

High blood pressure, or hypertension, makes your heart work a lot harder and, while doing so, causes excess force on your artery walls. Any added force can damage arteries and increase your risk of developing cardiovascular disease.

High blood pressure contributes to cardiovascular disease through the scarring of artery walls where plaque can build up and narrow the vessels. This causes a type of cardiovascular disease known as coronary artery disease. A narrowing artery can become completely blocked, leading to a heart attack. Also, plaques can break away from the artery wall and cause a blockage elsewhere.

High blood pressure has been called the silent killer because it often has no warning signs or symptoms.

People with high blood pressure are often not aware they have it until they are diagnosed by a health care professional. 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

Pre-hypertension indicates you have slightly surpassed the ideal target values and are at increased risk of developing high blood pressure, which may require medical therapy. If your systolic blood pressure is between 120 and 135 and/or your diastolic is between 80 and 85, you should take the necessary steps to decrease your blood pressure


Hypotension, otherwise known as low blood pressure, is a reading of less than 90/60. It can be just as serious and dangerous as high blood pressure and should not be ignored. Hypotension indicates that the force of your blood flow is inadequate, and this could mean certain of your vital organs are not receiving enough blood. Hypotension is a medical concern only if it causes signs or symptoms or is linked to a serious condition, such as heart disease. People who take certain high blood pressure medications, such as diuretics, have an increased risk for low blood pressure. 

What is considered low blood pressure may vary from person to person. 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

There are some risk factors you cannot control, and these put you at greater risk for high blood pressure. They include:

  • Age: About 50% of people older than the age of 65 have high blood pressure
  • Family history of high blood pressure
  • Ethnicity: High blood pressure is more common among people who are of African, South Asian, or First Nations descent.
  • Gender: The risk for women increases after menopause, putting them in even greater jeopardy than men.

There are two main causes, or types, of high blood pressure:

1. Primary Hypertension (also known as “essential hypertension”): Cases in which there is no easily identifiable cause for high blood pressure. The risk of developing essential hypertension increases with age. A number of lifestyle factors can increase the risk for essential hypertension, including:

  • Getting too much salt in the diet
  • Drinking alcohol excessively (males no more than two drinks a day; females one drink a day)
  • Being overweight
  • Getting insufficient exercise
  • Experiencing unmanageable stress

2. Secondary Hypertension: 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)