Hypertension is defined as having either chronically high diastolic blood pressure — the lower number that registers the pressure in the artery when the heart relaxes between beats — or high systolic blood pressure — the higher number that registers the pressure in the artery when the heart contracts. A person is considered to be hypertensive when systolic pressure is over 140mmHg most of the time or when diastolic pressure is over 90mmHg most of the time, according to the National Institutes of Health.

In the United States, approximately 32 percent of adults ages 20 and older have hypertension and 53 percent of nursing home residents have hypertension, according to  the Centers for Disease Control and Prevention. However, approximately 17 percent of individuals with hypertension are unaware of their condition, according to the Public Health Agency of Canada, and it's very likely that the overall prevalence of hypertension in the population a bit higher. The World Health Organization estimates that 1.2 billion people worldwide will suffer from hypertension by 2010.

Symptoms & Causes

Most people with high blood pressure don't have any overt symptoms, even if their blood pressure might be dangerously high. However, a few people might experience severe headaches, confusion, fatigue, irregular heartbeats, vision changes, dizzy spells and other symptoms, according to the Mayo Clinic.

Hypertension that is related to another disease — such as chronic kidney disease, diabetes, endocrine disorder and sleep apnea —is known as secondary hypertension. However, the cause for hypertension is sometimes not identifiable. This is known as essential hypertension and, according to the NIH, this is the more common type of hypertension.

Diet can also play a major role in the regulation of blood pressure and onset of hypertension. ‘About 30 percent of hypertension is due to excessive dietary sodium and, based on data from the 2004 Canadian Community Health Survey, as many as 90 percent of adult men and 65 percent of adult women consume beyond the upper limit of sodium in their meals.

Although some might think that stress could cause high blood pressure, a 2008 study that looked at 1,484 adults ages 18 to 60 in Brazil shows that once adjusted for other factors such as age, body mass index and family history, stressed people are no more likely than the general population to be diagnosed with hypertension. The authors suggested that the correlation between stress and hypertension may in fact be due to negative feelings about the disease rather than the disease itself.

Diagnosis & Tests

Routine assessment of blood pressure is recommended during all visits to the doctor. Once it's established that the patient has chronic high blood pressure, the doctor might order additional urinalysis and tests to measure blood glucose, HDL and LDL cholesterol and serum potassium. But more extensive testing is generally not ordered unless patients have trouble controlling blood pressure or a secondary cause is strongly suspected, according to the National Heart Lung and Blood Institute.' In this case, the diagnostic tests will vary depending on the possible cause — for example, tests for glomerular filtration rate if chronic kidney disease is suspected, or CT angiography if congenital narrowing of the aorta is suspected.

People with hypertension are also encouraged to measure their own blood pressure at home, so that they are more aware of any day-to-day changes, according to the Mayo Clinic.

Treatments & Medication

Conventional drugs for treating hypertension include thiazide diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blocker (ARB). Though doctors often prescribe more than two types of medication to effectively control blood pressure, the exact dosage and combination of medication largely depend on patients' medical history, race and age. For example, recommendations from the latest 2009 Canadian Hypertension Education Program discourages the combination of ACE inhibitor and ARB for patients with uncomplicated hypertension or previous stroke, yet this combination of drugs would be appropriate for patients who have a history of heart failure(s). Additional consideration should also be made for patients who can be negatively affected by low blood pressure, such as elderly patients.

Healthy Living Tips

Clinical studies have conclusively shown that a variety of lifestyle modifications — including weight loss for individuals who are overweight or obese, aerobic exercises, moderation of alcohol intake and a diet with plenty of fresh fruits and vegetables and reduced saturated fats and sodium — can help lower blood pressure and decrease the likelihood of hypertension. In fact, lifestyle modifications might even complement antihypertensive drugs and allow medication to be more effective, according to the National Heart Lung and Blood Institute. In general, most lifestyle improvements are cheaper and have less adverse side effects than medication, and beneficial effects can extend to other conditions such as type 2 diabetes and other cardiovascular diseases.