Low blood pressure (hypotension) is pressure so low it causes symptoms or signs due to the low flow of blood through the arteries and veins. When the flow of blood is too low to deliver enough oxygen and nutrients to vital organs such as the brain, heart, and kidney, the organs do not function normally and may be temporarily or permanently damaged.
Blood pressure is recorded as two numbers and written as a ratio: the top number, called the systolic pressure, is the pressure as the heart beats. The bottom number, called the diastolic pressure, is the measurement as the heart relaxes between beats. According to guidelines announced in November 2017 by the American Heart Association (AHA), people's blood pressure measurements fall into the following categories:
Low blood pressure is not always a sign of a problem. But if you have symptoms of low blood pressure, your doctor can diagnose the condition and uncover the cause. Symptoms of dizziness and lightheadedness when you stand up from sitting or lying down -- with a decrease in your blood pressure -- may indicate a condition called postural hypotension. A wide range of underlying conditions may also cause your symptoms. It's important to identify the cause of low blood pressure so appropriate treatment can be given.
Changes in blood vessel structure. Blood vessels have layers of the proteins elastin and collagen. Elastin is what makes blood vessels flexible. Collagen, which is stiffer, gives vessels structure. With age, elastin breaks down. Even the elastin that remains becomes less elastic. Meanwhile, collagen deposits in the vessels increase. As a result, blood vessels grow thicker and bend less easily over time. These changes may lead to higher systolic blood pressure.
^ Aronow WS, Fleg JL, Pepine CJ, Artinian NT, Bakris G, Brown AS, Ferdinand KC, Ann Forciea M, Frishman WH, Jaigobin C, Kostis JB, Mancia G, Oparil S, Ortiz E, Reisin E, Rich MW, Schocken DD, Weber MA, Wesley DJ, Harrington RA, Bates ER, Bhatt DL, Bridges CR, Eisenberg MJ, Ferrari VA, Fisher JD, Gardner TJ, Gentile F, Gilson MF, Hlatky MA, Jacobs AK, Kaul S, Moliterno DJ, Mukherjee D, Rosenson RS, Stein JH, Weitz HH, Wesley DJ (2011). "ACCF/AHA 2011 expert consensus document on hypertension in the elderly: a report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents developed in collaboration with the American Academy of Neurology, American Geriatrics Society, American Society for Preventive Cardiology, American Society of Hypertension, American Society of Nephrology, Association of Black Cardiologists, and European Society of Hypertension". J Am Soc Hypertens. 5 (4): 259–352. doi:10.1016/j.jash.2011.06.001. PMID 21771565.
The findings mean that an additional 14 percent of U.S. adults, or about 30 million people, will now be diagnosed as having high blood pressure, compared with the number diagnosed before the new guidelines. This will bring the total percentage of U.S. adults with high blood pressure to 46 percent, up from 32 percent previously. [9 New Ways to Keep Your Heart Healthy]

Changes in blood vessel function. The lining of blood vessels sustains more damage over time. This may be caused by oxidative stress or DNA damage, among other factors. With age, levels of the hormone angiotensin also rise, triggering inflammation in blood vessels. At the same time, vessels slowly lose the ability to release substances that protect or repair the lining. When the blood vessel lining does not work as well, higher diastolic blood pressures can result.
If your blood pressure is above the normal range for up to 5 readings (taken at different visits), your doctor will likely diagnose you with high blood pressure. Sometimes the doctor may diagnose you after a fewer number of readings, depending on how high above normal your blood pressure is and if you have other medical conditions. Blood pressure tends to be at its highest during exercise, physical work, or stress, and lowest during sleep. Everyone can have a temporary increase in blood pressure at one time or another, which is why it's important to take multiple readings.
Hypertension with certain specific additional signs and symptoms may suggest secondary hypertension, i.e. hypertension due to an identifiable cause. For example, Cushing's syndrome frequently causes truncal obesity, glucose intolerance, moon face, a hump of fat behind the neck/shoulder (referred to as a buffalo hump), and purple abdominal stretch marks.[23] Hyperthyroidism frequently causes weight loss with increased appetite, fast heart rate, bulging eyes, and tremor. Renal artery stenosis (RAS) may be associated with a localized abdominal bruit to the left or right of the midline (unilateral RAS), or in both locations (bilateral RAS). Coarctation of the aorta frequently causes a decreased blood pressure in the lower extremities relative to the arms, or delayed or absent femoral arterial pulses. Pheochromocytoma may cause abrupt ("paroxysmal") episodes of hypertension accompanied by headache, palpitations, pale appearance, and excessive sweating.[23]
A slow heart rate (bradycardia) can decrease the amount of blood pumped by the heart. The resting heart rate for a healthy adult is between 60 and 100 beats/minute. Bradycardia (resting heart rates slower than 60 beats/minute) does not always cause low blood pressure. In fact, some highly trained athletes can have resting heart rates in the 40s and 50s (beats per minute) without any symptoms. The slow heart rates are offset by more forceful contractions of the heart that pump more blood than in non-athletes. However, in many patients bradycardia can lead to low blood pressure, lightheadedness, dizziness, and even fainting.
Dizziness : While dizziness can be a side effect of some blood pressure medications, it is not caused by high blood pressure. However, dizziness should not be ignored, especially if the onset is sudden. Sudden dizziness, loss of balance or coordination and trouble walking are all warning signs of a stroke. High blood pressure is a leading risk factor for stroke.

The guidelines also redefined the various categories of hypertension. It eliminated the category of prehypertension, which had been defined as systolic blood pressure of 120 to 139 mm Hg or diastolic pressure (the lower number in a reading) of 80 to 89 mm Hg. Instead, people with those readings are now categorized as having either elevated pressure (120 to 129 systolic and less than 80 diastolic) or Stage 1 hypertension (130 to 139 systolic or 80 to 89 diastolic).


Exercise is another lifestyle factor that can lower blood pressure. It's recommended that adults get about 150 minutes per week of moderate exercise. This can include cardiovascular exercises such as walking, bicycling, gardening, or other aerobic exercise. Muscle-strengthening activities are recommended at least twice a week and stretching makes you more flexible and helps prevent injuries. Check with your doctor if you are currently inactive and want to start exercising. Make exercise fun by doing activities you enjoy or find an exercise buddy to join you!
Factors that increase your blood pressure can cause elevated levels. Medications such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers, and some prescription drugs may cause a temporary rise in blood pressure. The buildup of fatty deposits in the arteries (atherosclerosis) can also lead to prehypertension. Other conditions that may lead to prehypertension include the following:
If your blood pressure readings are consistently high, you and your doctor will probably discuss treatment strategies. Treatment for high blood pressure often begins with lifestyle changes such as a weight loss and exercise program as well as a low sodium diet. In fact, the AHA recommends adopting these strategies as a means of preventing the development of high blood pressure and heart disease. If these strategies are not successful in lowering your blood pressure, medications may be recommended.
"Having a healthy lifestyle really makes a difference in your life because you can avoid high blood pressure," said Dr. Mary Ann Bauman, an internist at Integris Baptist Medical Center in Oklahoma City. "If you do have high blood pressure, make sure take your medication. You may not necessarily have symptoms until your blood pressure gets really high."
Remember, though, there are many steps you can take to lower your blood pressure. It’s important to work together with your health care team to set your blood pressure goal—the reading you’d like to consistently see when your blood pressure is taken—and how you can best reach it. If you have coronary artery disease, diabetes or chronic kidney disease, managing high blood pressure is especially important.
Researchers at the University of Melbourne and Macquarie University have uncovered unusual activity between neurons controlling breathing and blood pressure during the development of essential hypertension. Essential hypertension, which is high blood pressure with no known cause, affects 30% of the global population and is a major contributor to cardiovascular disease.
There are even more medication types that can lower blood pressure. Some of these are alpha blockers, vasodilators, and central alpha agonists. Your doctor may prescribe these medications if other medications have been ineffective or if you have another condition along with hypertension. Side effects can include fast pulse, palpitations, dizziness, diarrhea, or headaches.
There is no treatment available for the causes of portal hypertension. However, treatment can prevent or manage the complications. Diet, medication (nonselective beta-blockers), endoscopic therapy, surgery, and radiology procedures can all help in treating or preventing symptoms of portal hypertension. If these treatments are unsuccessful in treating symptoms, transjugular intrahepatic portosystemic shunt (TIPS) or distal splenorenal shunt (DSRA) are two procedures that may reduce pressure in the portal veins. Maintaining a healthy lifestyle may help to prevent portal hypertension.
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