The heart is a muscle that pumps blood around the body. As it travels, the blood delivers oxygen to the body's vital organs.Sometimes, a problem in the body makes it harder for the heart to pump the blood. This could happen, for example, if an artery becomes too narrow.Persistent high blood pressure can put a strain on the walls of the arteries. This can lead to a variety of health problems, some of which can be life threatening.

Most people with high blood pressure will not experience any symptoms, which is why people often call hypertension the "silent killer."

However, once blood pressure reaches about 180/120 mm Hg, it becomes a hypertensive crisis, which is a medical emergency.

At this stage, a person may have:

•     a headache
•     nausea
•     vomiting
•     dizziness
•     blurred or double vision
•     nosebleeds
•     heart palpitations
•     breathlessness.

Hormonal factors mean that the risk of high blood pressure may be different in males and females.

Factors that can increase the risk of high blood pressure in females include:

•     pregnancy
•     menopause
•     the use of birth control pills.

During pregnancy, high blood pressure can be a sign of preeclampcia, a potentially dangerous condition that can affect the woman and her unborn baby.

Symptoms of preeclampsia include:

Symptoms of preeclampsia include:

•     headaches
•     vision changes
•     abdominal pain
•     swelling due to edema.

High blood pressure can occur when certain changes happen in the body or if a person is born with specific genetic features that cause a health condition.

It can affect people with:

•     obesity
•     type 2 diabetes
•     kidney disease
•     obstructive sleep apnea
•     lupus
•     scleroderma
•     underactive or overactive thyroid
•     congenital conditions, such as Cushing's syndrome, acromegaly, or pheochromocytoma

Sometimes, there is no apparent cause. In this case, a doctor will diagnose primary hypertension.

Consuming a high fat diet, carrying excess weight, drinking a lot of alcohol, smoking tobacco, and the use of some medications also increase the risk.