High blood pressure (hypertension) is an increase in pressure inside the arteries, the vessels that carry blood from the heart. This is usually caused by constriction, or narrowing, of the arteries. The heart then has to work harder to pump blood to the rest of the body.
This increase in pressure eventually causes damage to the walls of the arteries. If untreated, high blood pressure can lead to many problems throughout the body, particularly in the heart, brain and kidneys. Eventually, high blood pressure can cause a heart attack or stroke. It is also a major factor in the development of dementia. High blood pressure is often called “the silent killer” because it usually has no symptoms.
Your blood pressure is considered high if you have systolic pressure of 140 mmHg or more and/or diastolic pressure of 90 mmHg or more. At these levels, the force of blood against the walls of your arteries is too high and the workload on your heart is increased.
High blood pressure is the number one risk factor for stroke and a major risk factor for heart disease. The chance of stroke, heart attack and congestive heart failure are dramatically reduced when patients have their blood pressure successfully managed through lifestyle changes and/or medication.
For most people with high blood pressure, there is no identifiable cause. This is called essential hypertension. In general, family history (genetics) and lifestyle contribute. Your risk of developing essential hypertension increases with age. Lifestyle factors can also increase your risk of essential hypertension, including:
- Being overweight
- Excessive alcohol (males, no more than two drinks a day; females, one drink a day)
- Too much salt in your diet
- Lack of exercise
In some people, high blood pressure does have an identifiable cause. This is called secondary hypertension. Common causes of secondary hypertension include:
- Kidney disease
- Hormone disorders
- Certain drugs (such as birth control pills and NSAIDs)
- Sleep apnea (repeated, short stops in breathing while sleeping)
High blood pressure does not usually cause symptoms. Many people with high blood pressure are not aware that they have the condition.
If high blood pressure is severe, you may have symptoms that include:
- Severe headache
- Shortness of breath
- Nausea and vomiting
- Vision problems
Regular and ongoing blood pressure monitoring is important for your heart health. Your blood pressure should be checked annually if it is within normal limits (<130/80) and should be checked more often if it is higher than 140/90. If your blood pressure stays high over time, treatment should be considered.
Diagnosis of essential hypertension is made after potential secondary causes are ruled out.
Your blood pressure should be measured when you are seated in a chair with your back supported, feet flat on the floor, and an arm supported at heart level. It is very important to use the proper size cuff. Not doing so will lead to inaccurate readings. A cuff that is too small for your arm will give a high reading. A cuff that is too large will give a low reading.
Blood pressure should be measured in both arms to make sure the readings are the same. If one arm has higher readings, that arm should be used for future readings.
If your reading is high, you should take additional measurements on different days, because blood pressure can vary widely from day to day. Stress, pain or just talking can increase your blood pressure. Patterns often seen with high blood pressure include:
- White coat hypertension: Blood pressure is primarily elevated in the doctor's office from the anxiety of a clinical visit and is lower or not elevated with normal activities.
- Sustained hypertension: Blood pressure is consistently above 135/85 mm Hg during the day.
- Masked hypertension: Blood pressure is more elevated when measured at home or at work than in the doctor's office.
- Non-dipping: Blood pressure does not decrease during the night.
Common tests that may be ordered to help your doctor diagnose hypertension include:
- Blood tests to measure your electrolytes, blood sugar, lipids, and kidney function
- A urine tested to detect blood, sugar or protein in your urine
- An electrocardiogram (ECG) or echocardiogram (ultrasound of the heart) to check for evidence of a previous heart attack or for damage to your heart from high blood pressure
- Kidney tests such as abdominal ultrasound, CT scan and renal angiogram
- 24-hour ambulatory blood pressure monitoring automatically reads your blood pressure every 20 to 20 minutes to better assess changes throughout the day and your risk for future cardiovascular disease
High blood pressure can be lowered with lifestyle changes and medications. Only a properly trained health care professional can determine the appropriate approaches for your specific situation.
Doctors often first advise lifestyle changes, such as:
- Losing weight and eating a healthy diet such as the DASH diet (rich in fruits and vegetables, low-fat dairy, reduce saturated and total fat)
- Reducing salt (no more than 1,500 mg per day)
- Reducing alcohol intake (males, no more than two drinks per day and females, no more than one drink per day)
- Getting more exercise (at least 30 mins per day, most days of the week)
- Managing stress
The same lifestyle changes used to lower high levels of blood pressure can also help to prevent it.
If your blood pressure is not lowered after several months of lifestyle changes, or if very high blood pressure is a concern, you may need to take medications in addition to trying to maintain a healthy lifestyle. Many options are available including:
- Diuretics (water pill): to remove excess salt in the body
- Beta blockers: to slow the heartbeat
- ACE inhibitors, calcium channel blockers, angiotensin II receptor blockers and vasodilators: to relax and/or widen the blood vessels
- Alpha blockers: to block nerve impulses that tighten the blood vessels
- Nervous system inhibitors: to decrease nerve impulses that tighten the blood vessels