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.

"The implications and potential benefits of such healthier lifestyles could be great, particularly since about 22% of the adult population falls into the prehypertensive category," says Chobanian, who is also dean of the Boston University School of Medicine. "In fact, the blood pressure effects of weight reduction or adoption of the DASH eating plan can be comparable to those achieved with any single blood pressure medication."
In people aged 18 years or older hypertension is defined as either a systolic or a diastolic blood pressure measurement consistently higher than an accepted normal value (this is above 129 or 139 mmHg systolic, 89 mmHg diastolic depending on the guideline).[5][7] Other thresholds are used (135 mmHg systolic or 85 mmHg diastolic) if measurements are derived from 24-hour ambulatory or home monitoring.[79] Recent international hypertension guidelines have also created categories below the hypertensive range to indicate a continuum of risk with higher blood pressures in the normal range. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC7) published in 2003[27] uses the term prehypertension for blood pressure in the range 120–139 mmHg systolic or 80–89 mmHg diastolic, while European Society of Hypertension Guidelines (2007)[86] and British Hypertension Society (BHS) IV (2004)[87] use optimal, normal and high normal categories to subdivide pressures below 140 mmHg systolic and 90 mmHg diastolic. Hypertension is also sub-classified: JNC7 distinguishes hypertension stage I, hypertension stage II, and isolated systolic hypertension. Isolated systolic hypertension refers to elevated systolic pressure with normal diastolic pressure and is common in the elderly.[27] The ESH-ESC Guidelines (2007)[86] and BHS IV (2004)[87] additionally define a third stage (stage III hypertension) for people with systolic blood pressure exceeding 179 mmHg or a diastolic pressure over 109 mmHg. Hypertension is classified as "resistant" if medications do not reduce blood pressure to normal levels.[27] In November 2017, the American Heart Association and American College of Cardiology published a joint guideline which updates the recommendations of the JNC7 report.[88]
A single lower-than-normal reading is not cause for alarm, unless you are experiencing any other symptoms or problems. If you experience any dizziness, lightheadedness, nausea or other symptoms, it’s a good idea to consult with your healthcare provider. To help with your diagnosis, keep a record of your symptoms and activities at the time they occurred.
Mountains of research over time have shown a very clear link between high blood pressure and cardiovascular disease. A 20-point higher systolic blood pressure or a 10-point higher diastolic blood pressure is associated with double your risk of death from a heart attack, stroke, or other cardiovascular complication (like abdominal aortic aneurysm or heart failure). What many people don’t realize is that those who survive these events find their lives permanently altered by disability and medical complications. 

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels and constitutes one of the principal vital signs. The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, and veins; the term blood pressure generally refers to arterial pressure, i.e., the pressure in the larger arteries, arteries being the blood vessels which take blood away from the heart.
High blood pressure often runs in families. Much of the understanding of the body systems involved in high blood pressure has come from genetic studies. Research has identified many gene variations associated with small increases in the risk of developing high blood pressure. New research suggests that certain DNA changes during fetal development may also lead to the development of high blood pressure later in life.
^ Jump up to: a b Semlitsch, T; Jeitler, K; Berghold, A; Horvath, K; Posch, N; Poggenburg, S; Siebenhofer, A (2 March 2016). "Long-term effects of weight-reducing diets in people with hypertension". The Cochrane Database of Systematic Reviews. 3: CD008274. doi:10.1002/14651858.CD008274.pub3. PMID 26934541. Archived from the original on 23 March 2016. Retrieved 9 March 2016.
You may be directed to seek medical care if blood pressure readings are elevated if done as part of a community health screening. Isolated elevated blood pressure readings do not necessarily make the diagnosis of hypertension. Blood pressure readings vary throughout the day, and your primary care provider may record a different reading than the one that was measured in a screening that sent you in for care.
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.
^ Qaseem, A; Wilt, TJ; Rich, R; Humphrey, LL; Frost, J; Forciea, MA; Clinical Guidelines Committee of the American College of Physicians and the Commission on Health of the Public and Science of the American Academy of Family, Physicians. (21 March 2017). "Pharmacologic Treatment of Hypertension in Adults Aged 60 Years or Older to Higher Versus Lower Blood Pressure Targets: A Clinical Practice Guideline From the American College of Physicians and the American Academy of Family Physicians". Annals of Internal Medicine. 166 (6): 430–437. doi:10.7326/m16-1785. PMID 28135725.
Some people may ask why doctors are lowering the threshold for high blood pressure, when it was already difficult for many patients to achieve the previous blood pressure targets of below 140 mm Hg/90 mm Hg, said Dr. Pamela B. Morris, a preventive cardiologist and chairwoman of the ACC's Prevention of Cardiovascular Disease Leadership Council. However, Morris said that the guidelines were changed because "we now have more precise estimates of the risk of [high] blood pressures," and these new guidelines really communicate that risk to patients. So, just because it's going to be difficult for people to achieve, "I don't think it's a reason not to communicate the risk to patients, and to empower them to make appropriate lifestyle modifications," Morris told Live Science.
Medicines are available if these changes do not help control your blood pressure within 3 to 6 months. Diuretics help rid your body of water and sodium. ACE inhibitors block the enzyme that raises your blood pressure. Other types of medicines— beta blockers, calcium channel blockers, and other vasodilators—work in different ways, but their overall effect is to help relax and widen your blood vessels and reduce the pressure inside the vessel. [See also the free government publication “Medicines to Help You: High Blood Pressure” (PDF) from the US Food and Drug Administration.]
High blood pressure is the most common chronic medical problem prompting visits to primary health care providers in USA. The American Heart Association estimated the direct and indirect costs of high blood pressure in 2010 as $76.6 billion.[144] In the US 80% of people with hypertension are aware of their condition, 71% take some antihypertensive medication, but only 48% of people aware that they have hypertension adequately control it.[144] Adequate management of hypertension can be hampered by inadequacies in the diagnosis, treatment, or control of high blood pressure.[164] Health care providers face many obstacles to achieving blood pressure control, including resistance to taking multiple medications to reach blood pressure goals. People also face the challenges of adhering to medicine schedules and making lifestyle changes. Nonetheless, the achievement of blood pressure goals is possible, and most importantly, lowering blood pressure significantly reduces the risk of death due to heart disease and stroke, the development of other debilitating conditions, and the cost associated with advanced medical care.[165][166]
As blood travels throughout your body, it presses against the walls of your blood vessels, just like water in a hose or air in a tire. This is called blood pressure. When your heart beats (contracts), squeezing blood out and pumping it into your arteries, blood pressure peaks. This is called your systolic pressure. Between heartbeats, when your heart relaxes and blood flows back into it, your blood pressure is lower. This is your diastolic pressure.

^ Ostchega Y, Dillon CF, Hughes JP, Carroll M, Yoon S (July 2007). "Trends in hypertension prevalence, awareness, treatment, and control in older U.S. adults: data from the National Health and Nutrition Examination Survey 1988 to 2004". Journal of the American Geriatrics Society. 55 (7): 1056–65. doi:10.1111/j.1532-5415.2007.01215.x. PMID 17608879.

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]
Blood pressure is given as a reading of two numbers, such as 110/70. The higher number (systolic) is the pressure when the heart beats. The diastolic, or lower number shows the pressure between the heartbeats, while the relaxed heart is refilling with blood. Normal blood pressure readings are lower than 120/80. The cause of most hypertension is unknown. Occasionally, conditions of the kidney or adrenal gland are the cause of high blood pressure.
The most widely used classification of blood pressure readings currently is given in the table below. Stratification of the blood pressure readings into different categories is important because of increasing severity of high blood pressure readings and different approach to the treatment of these conditions. Another table below the first one gives the blood pressure chart with different categories of the blood pressure, symptoms and the treatment.
NHLBI-funded Research Supports Development of Guidelines for High Blood Pressure Management. The Systolic Blood Pressure Intervention Trial (SPRINT) found that treating to a lower systolic blood pressure target—less than 120 mm Hg—reduced complications from high blood pressure and saved lives. SPRINT results informed recent high blood pressure clinical guidelines that aim to improve treatment for millions of people. SPRINT Memory and Cognition in Decreased Hypertension (SPRINT-MIND) is examining whether treating to the lower blood pressure target can reduce the rate of dementia and slow cognitive decline in the SPRINT participants.
Our free blood pressure chart and blood pressure log allow you to track your blood pressure, aiding you in being aware of and gaining control over your blood pressure and health. Since normal blood pressure levels can change with age, weight, height and many other factors, you should consult your doctor or caregiver to determine your appropriate target blood pressure, which can be entered into the blood pressure log. The blood pressure charts below are a quick reference for low, normal and high blood pressures.

Heart attack. Signs of heart attack include mild or severe chest pain or discomfort in the center of the chest or upper abdomen that lasts for more than a few minutes or goes away and comes back. It can feel like pressure, squeezing, fullness, heartburn, or indigestion. There may also be pain down the left arm. Women may also have chest pain and pain down the left arm, but they are more likely to have less typical symptoms, such as shortness of breath, nausea, vomiting, unusual tiredness, and pain in the back, shoulders, or jaw. Read more about the signs and symptoms of a heart attack.
The range of systolic blood pressure for most healthy adults falls between 90 and 120 millimeters of mercury (mm Hg). Normal diastolic blood pressure ranges between 60 and 80 mm Hg. Current guidelines define normal blood pressure range as lower than 120/80. Blood pressures over 130/80 are considered high. High blood pressure increases the risk of damaging the arteries, which leads to the development of:
It occurs more often in older people who are taking a lot of medication. However, it can cause symptoms in younger people. There may be underlying medical conditions such as joint hypermobility syndrome, diabetes, parkinson’s disease, addison’s disease or autonomic failure. Dehydration, hunger, low body weight and deconditioning (being out of shape/unfit) can reduce blood pressure.

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.

Blood pressure is measured with a blood pressure cuff (sphygmomanometer). This may be done using a stethoscope and a cuff and gauge or by an automatic machine. It is a routine part of the physical examination and one of the vital signs often recorded for a patient visit. Other vital signs include pulse rate, respiratory rate (breathing rate), temperature, and weight.

Blood tests may be done to assess risk factors for heart disease and stroke as well as looking for complications of hypertension. These include complete blood count (CBC), electrolytes, BUN (blood urea nitrogen), and creatinine and GFR (glomerular filtration rate) to measure kidney function. A fasting lipid profile will measure cholesterol and triglyceride levels in the blood. If appropriate, blood tests may be considered to look for an underlying cause of high blood pressure (secondary hypertension)including abnormal thyroid or adrenal gland function.

For a normal reading, your blood pressure needs to show a top number (systolic pressure) that’s between 90 and less than 120 and a bottom number (diastolic pressure) that’s between 60 and less than 80. The American Heart Association (AHA) considers blood pressure to be within the normal range when both your systolic and diastolic numbers are in these ranges.
The value of routine screening for hypertension in children over the age of 3 years is debated.[90][91] In 2004 the National High Blood Pressure Education Program recommended that children aged 3 years and older have blood pressure measurement at least once at every health care visit[89] and the National Heart, Lung, and Blood Institute and American Academy of Pediatrics made a similar recommendation.[92] However, the American Academy of Family Physicians[93] supports the view of the U.S. Preventive Services Task Force that the available evidence is insufficient to determine the balance of benefits and harms of screening for hypertension in children and adolescents who do not have symptoms.[94]
For a normal reading, your blood pressure needs to show a top number (systolic pressure) that’s between 90 and less than 120 and a bottom number (diastolic pressure) that’s between 60 and less than 80. The American Heart Association (AHA) considers blood pressure to be within the normal range when both your systolic and diastolic numbers are in these ranges.
We stimulate high-impact research. Our Trans-Omics for Precision Medicine (TOPMed) Program includes participants with high blood pressure, which may help us understand how genes contribute to differences in disease severity and how patients respond to treatment. The NHLBI Strategic Vision highlights ways we may support research over the next decade, including new efforts for studying high blood pressure.

With age, comes an increased risk for systolic hypertension which can be aggravated by severe atherosclerosis. According to one study, the diuretic chlorthalidone (Hygroton) had significant benefit in elderly patients with systolic hypertension. Along with a diuretic, some calcium channel blockers, ACE inhibitors and angiotensin II receptor blockers may also be good choices. However, beta blockers may not be as effective for hypertension in those over 60; though they may be good choices if co-existing heart disease is present. It also may be preferable in elderly patients to give two high blood pressure medications at a low dose versus one at a higher dose.
tilt table test – usually recommended if your doctor suspects you might have orthostatic hypotension or NMH (During this diagnostic test, a person lies on a table and then the table is tilted to raise the upper part of their body. This simulates the change in position from sitting or lying down to standing up. People with orthostatic hypotension or NMH may feel dizzy, lightheaded, or even faint when their position changes.)
Many expert groups recommend a slightly higher target of 150/90 mmHg for those over somewhere between 60 and 80 years of age.[99][100][101][105] The JNC-8 and American College of Physicians recommend the target of 150/90 mmHg for those over 60 years of age,[13][106] but some experts within these groups disagree with this recommendation.[107] Some expert groups have also recommended slightly lower targets in those with diabetes[99] or chronic kidney disease with protein loss in the urine,[108] but others recommend the same target as for the general population.[13][103] The issue of what is the best target and whether targets should differ for high risk individuals is unresolved,[109] although some experts propose more intensive blood pressure lowering than advocated in some guidelines.[110]
If you have high blood pressure, it is important to get routine medical care and to follow your prescribed treatment plan, which will include heart-healthy lifestyle changes and possibly medicines. Heart-healthy lifestyle changes can prevent high blood pressure, reduce elevated blood pressure, help control existing high blood pressure, and prevent complications, such as heart attack, heart failure, stroke, vascular dementia, or chronic kidney disease.
^ Saiz, Luis Carlos; Gorricho, Javier; Garjón, Javier; Celaya, Mª Concepción; Muruzábal, Lourdes; Malón, Mª del Mar; Montoya, Rodolfo; López, Antonio (2017-10-11). "Blood pressure targets for the treatment of people with hypertension and cardiovascular disease". Cochrane Database of Systematic Reviews. 10: CD010315. doi:10.1002/14651858.cd010315.pub2. PMID 29020435.
In Europe hypertension occurs in about 30-45% of people as of 2013.[12] In 1995 it was estimated that 43 million people (24% of the population) in the United States had hypertension or were taking antihypertensive medication.[141] By 2004 this had increased to 29%[142][143] and further to 32% (76 million US adults) by 2017.[7] In 2017, with the change in definitions for hypertension, 46% of people in the United States are affected.[7] African-American adults in the United States have among the highest rates of hypertension in the world at 44%.[144] It is also more common in Filipino Americans and less common in US whites and Mexican Americans.[6][145] Differences in hypertension rates are multifactorial and under study.[146]
Allergic reaction (anaphylaxis): Anaphylactic shock is a sometimes-fatal allergic reaction that can occur in people who are highly sensitive to drugs such as penicillin, to certain foods such as peanuts or to bee or wasp stings. This type of shock is characterized by breathing problems, hives, itching, a swollen throat and a sudden, dramatic fall in blood pressure.