HYPERTENSION  
  INTRODUCTION  
 

Hypertension, or high blood pressure, is a condition in which a person's blood pressure is persistently above normal. It is a major disorder that plays an important role as a risk factor in disease, and left untreated it can have serious consequences such as damage to the heart, blood vessels, brain, kidneys and eyes. Hypertension occurs in all types of people and is very common, affecting about 1 in every 5 adults in North America. The incidence increases with age in all groups, and it generally occurs earlier and more often in men than in women.

 
  WHAT IS HIGH BLOOD PRESSURE?  
 

Blood pressure is the measure of the force generated by the heart as it pumps blood through the arterial system to all parts of your body, and therefore also the pressure that the blood exerts against the walls of the arteries. The amount of pressure depends upon the strength and the rate of the heart's contraction, the volume of blood in the circulatory system, and the size and elasticity of the arteries. Many other factors can affect blood pressure, including volume of water in the body, salt content of the body, condition of the kidneys, nervous system, or blood vessels,
and levels of various hormones in the body.

 
 

There is only one way to find out if you have high blood pressure have your blood pressure checked by your doctor or nurse. One high blood pressure reading does not always mean you have high blood pressure - it takes several readings to know for sure. If your blood pressure becomes high and stays high, your doctor will say you have "hypertension" - the medical word for high blood pressure.

 
 

The heart is a muscular pump, and when measuring blood pressure, two readings are taken which correspond to the two main stages in the pumping action of the heart. Thus the pressure is expressed as two numbers, such as 110 over 80 mm Hg (millimetres of mercury) - in everyday use a nurse or doctor may simply say your blood pressure is "110 over 80."

  
 

The first and higher number is called the "systolic" blood pressure. This is the pressure in the system when the heart contracts or beats, and it represents the amount of force used by the heart to initially fill the blood vessel circuit. The second and lower number is the "diastolic" blood pressure. This is the pressure in the system when the heart relaxes between beats, and is a measure of the resistance to the force of contraction.

 
 

Combined, these numbers give your healthcare provider a picture of how hard your heart is working to get blood to the tissues in your body.

 
  Normal blood pressure  
 

Blood pressure is normal when the higher number is below 130 and the lower number is below 85. For example, 125 over 80 (125/80) is normal blood pressure.

 
  High normal blood pressure  
  Blood pressure between 130/85 and 139/89 is high normal and should be rechecked every year.  
  High blood pressure  
  Blood pressure of 140/90 or over is high.  
 

High blood pressure, or hypertension, is blood pressure that consistently reads above 140 over 90 mm Hg. High blood pressure causes undue stress to the circulation of key organs, particularly the heart, brain and kidneys. This leads to significantly increased risk of heart attack, stroke and kidney failure; with extremely high blood pressure, retinal damage and encephalopathy (brain tissue dysfunction) can occur. High blood pressure can also cause an aneurysm, a small balloon-like weakening of the artery wall, which can be life threatening.

 
  Hypertension can be especially hard to manage when combined with other disorders, such as diabetes or obesity.