Hypertension or high blood pressure is a chronic medical condition in which the blood pressure in the arteries is higher than it should be. This involves the heart  working harder than normal to circulate blood through the blood vessels.

Blood pressure 

The pressure in the arteries changes depending on what the heart is doing. When the heart squeezes, pumping blood into the arteries, the pressure increases. When the heart relaxes, the pressure decreases. When blood pressure is measured, the highest pressure (when the heart is squeezing) is called the systolic blood pressure. The lowest pressure (when the heart is relaxing) is called the diastolic blood pressure.

Blood pressure is written as two numbers. For example, in the picture at the right, the person's systolic blood pressure was 158. Their diastolic blood pressure was 99. This blood pressure is written as 158/99. It is said "158 over 99."

Types 
There are two types of hypertension, called “primary” and “secondary.” Primary hypertension means that the hypertension is not caused by any other disease or condition and it gradually develops over time with age. Secondary hypertension means that the hypertension is caused by another disease or conditions. Secondary hypertension tend to result in higher blood pressure than primary hypertension. In most cases (90-95%), hypertension is primary. Only a small amount of hypertension (5-10%) is secondary.

There are various health conditions that leads to secondary hypertension which includes: Obstructive sleep apnea, Kidney problems, Adrenal gland tumors, Thyroid problems, Certain defects you're born with (congenital) in blood vessels, Certain medications (birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs), Illegal drugs (cocaine and amphetamines).

Complications 
Hypertension can cause many problems, including heart attack, stroke, Aneurysm, congestive heart failure, kidney failure, vision loss, Metabolic syndrome, Dementia, etc..
 To stay healthy, most people should try to keep their blood pressure below 140/90 mmHg.

Risk Factors 
The risk factors includes age, Race, Family history or genes, obesity, lack of physical activity, chewing or smoking tobacco, too much salt in diet, not enough potassium in diet, alcohol, stress, kidney disease, diabetes and sleep apnea.

Treatment

Lifestyle changes 
Hypertension can often be fixed with changes in diet or lifestyle. The 2004 British Hypertension Society suggests that people with high blood pressure:
 Lose weight if they are overweight or obese
 Exercise regularly
 Decrease the amount of salt they eat
 Limit the amount of alcohol they drink
 Eat a lot of fruits and vegetables

Medicine 
If lifestyle changes do not decrease a person's blood pressure, then the person may need medications. A doctor will choose which medications to use, based on what other medical problems the person has. Examples of medications that decrease blood pressure include:
 Diuretics, which increase urination to get rid of extra fluid
 Beta blockers, which slow down the heart rate
 ACE inhibitors, which relax the arteries

Effectiveness 
Even small decreases in blood pressure can have a large effect on a person's health. For example, decreasing blood pressure by 5 mmHg (for example, from 150/100 to 145/95 mmHg) can decrease the risk of stroke by 34%. It can also decrease the risk of heart disease by 21%.

Related pages
 Blood pressure
 Heart
 Arteries
 Circulatory system
 Hypotension (low blood pressure)

References 

What is Blood Pressure Or Hypertension ? 

Diseases and disorders of the cardiovascular system