Your total blood pressure reading is determined by measuring your systolic and diastolic blood pressures. Systolic blood pressure, the top number, measures the force your heart exerts on the walls of your arteries each time it beats. Diastolic blood pressure, the bottom number, measures the force your heart exerts on the walls of your arteries in between beats.
We fund research. The research we fund today will help improve our future health. Our Division of Cardiovascular Sciences and its Vascular Biology and Hypertension Branch oversee much of the research we fund on the regulation of blood pressure, pathways involved in high blood pressure, and the complications from uncontrolled high blood pressure. The Center for Translation Research and Implementation Science supports research to translate these discoveries into clinical practice. Search the NIH RePORTer to learn about research NHLBI is funding on high blood pressure
Even occasional dizziness or lightheadedness may be a relatively minor problem — the result of mild dehydration from too much time in the sun or a hot tub, for example. Still, it's important to see your doctor if you have signs or symptoms of hypotension because they can point to more-serious problems. It can be helpful to keep a record of your symptoms, when they occur and what you're doing at the time.
Once the diagnosis of hypertension has been made, healthcare providers should attempt to identify the underlying cause based on risk factors and other symptoms, if present. Secondary hypertension is more common in preadolescent children, with most cases caused by kidney disease. Primary or essential hypertension is more common in adolescents and has multiple risk factors, including obesity and a family history of hypertension.[83] Laboratory tests can also be performed to identify possible causes of secondary hypertension, and to determine whether hypertension has caused damage to the heart, eyes, and kidneys. Additional tests for diabetes and high cholesterol levels are usually performed because these conditions are additional risk factors for the development of heart disease and may require treatment.[6]
Hypertension, the medical term for high blood pressure, is known as "the silent killer." More than 80 million Americans (33%) have high blood pressure, and as many as 16 million of them do not even know they have the condition. If left untreated, high blood pressure greatly increases your risk for heart attack and stroke. Hypertension is projected to increase about 8 percent between 2013 and 2030.

When a blood pressure reading is taken, the higher number represents the systolic pressure and the lower number represents the diastolic pressure. For example: 120/80 (120 over 80) in an adult means that the systolic pressure is 120 and the diastolic pressure is 80. As kids grow, their blood pressure increases from a systolic pressure of about 70–90 (as babies) to adult values (when they're teens).

"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."
^ Jump up to: a b Brook RD, Appel LJ, Rubenfire M, Ogedegbe G, Bisognano JD, Elliott WJ, Fuchs FD, Hughes JW, Lackland DT, Staffileno BA, Townsend RR, Rajagopalan S, American Heart Association Professional Education Committee of the Council for High Blood Pressure Research, Council on Cardiovascular and Stroke Nursing, Council on Epidemiology and Prevention, and Council on Nutrition, Physical, Activity (Jun 2013). "Beyond medications and diet: alternative approaches to lowering blood pressure: a scientific statement from the American Heart Association". Hypertension. 61 (6): 1360–83. doi:10.1161/HYP.0b013e318293645f. PMID 23608661.

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.
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.

These guidelines help guide healthcare practices, and can be related to patient reimbursement and healthcare coverage. The tenth revision of the International Statistical Classification of Diseases and Related Health Problems, or ICD-10, is the set of codes used to designate specific health conditions and allow for reimbursement through health insurance programs.
Postural hypotension is considered a failure of the cardiovascular system or nervous system to react appropriately to sudden changes. Normally, when you stand up, some blood pools in your lower extremities. Uncorrected, this would cause your blood pressure to fall. But your body normally compensates by sending messages to your heart to beat faster and to your blood vessels to constrict. This offsets the drop in blood pressure. If this does not happen, or happens too slowly, postural hypotension results and can lead to fainting.
Hypertension defined as elevated blood pressure over several visits affects 1% to 5% of children and adolescents and is associated with long term risks of ill-health.[89] Blood pressure rises with age in childhood and, in children, hypertension is defined as an average systolic or diastolic blood pressure on three or more occasions equal or higher than the 95th percentile appropriate for the sex, age and height of the child. High blood pressure must be confirmed on repeated visits however before characterizing a child as having hypertension.[89] Prehypertension in children has been defined as average systolic or diastolic blood pressure that is greater than or equal to the 90th percentile, but less than the 95th percentile.[89] In adolescents, it has been proposed that hypertension and pre-hypertension are diagnosed and classified using the same criteria as in adults.[89]
Hypertension defined as elevated blood pressure over several visits affects 1% to 5% of children and adolescents and is associated with long term risks of ill-health.[89] Blood pressure rises with age in childhood and, in children, hypertension is defined as an average systolic or diastolic blood pressure on three or more occasions equal or higher than the 95th percentile appropriate for the sex, age and height of the child. High blood pressure must be confirmed on repeated visits however before characterizing a child as having hypertension.[89] Prehypertension in children has been defined as average systolic or diastolic blood pressure that is greater than or equal to the 90th percentile, but less than the 95th percentile.[89] In adolescents, it has been proposed that hypertension and pre-hypertension are diagnosed and classified using the same criteria as in adults.[89]

Septicemia is a severe infection in which bacteria (or other infectious organisms such as fungi) enter the blood. The infection typically originates in the lungs (as pneumonia), bladder, or in the abdomen due to diverticulitis or gallstones. The bacteria then enter the blood where they release toxins and cause life-threatening and profound low blood pressure (septic shock), often with damage to several organs.
Another form of postural hypotension occurs typically in young healthy individuals. After prolonged standing, the individual's heart rate and blood pressure drop, causing dizziness, nausea, and often fainting. In these individuals, the autonomic nervous system wrongly responds to prolonged standing by directing the heart to slow down and the veins to dilate thereby removing blood from circulating in the arteries.
Severe high blood pressure is referred to as malignant hypertension, in which the diastolic ("bottom") blood pressure reading is over 140 mmHg. Malignant hypertension is a medical emergency and can cause stroke. Symptoms can include nausea, severe headache, blurred vision, and dizziness. Some people with malignant hypertension may develop kidney failure. They may experience a decrease in urine output and swelling (edema), most pronounced in the lower legs.
^ Mente, Andrew; O'Donnell, Martin; Rangarajan, Sumathy; Dagenais, Gilles; Lear, Scott; McQueen, Matthew; Diaz, Rafael; Avezum, Alvaro; Lopez-Jaramillo, Patricio; Lanas, Fernando; Li, Wei; Lu, Yin; Yi, Sun; Rensheng, Lei; Iqbal, Romaina; Mony, Prem; Yusuf, Rita; Yusoff, Khalid; Szuba, Andrzej; Oguz, Aytekin; Rosengren, Annika; Bahonar, Ahmad; Yusufali, Afzalhussein; Schutte, Aletta Elisabeth; Chifamba, Jephat; Mann, Johannes F E; Anand, Sonia S; Teo, Koon; Yusuf, S (July 2016). "Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies". The Lancet. 388 (10043): 465–75. doi:10.1016/S0140-6736(16)30467-6. PMID 27216139.
Some forms of postural hypotension may require a test called a "tilt table" test. This test evaluates the body's reaction to changes in position. The person lies on a table, is safely strapped in, and the table is raised to an upright position for up to an hour. Blood pressure, heart rate, and symptoms are recorded. Often, medications are given to help guide treatment.

^ 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.


Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is called systolic pressure. When your heart is at rest, between beats, your blood pressure falls. This is called diastolic pressure.
Effective lifestyle modification may lower blood pressure as much as an individual antihypertensive medication. Combinations of two or more lifestyle modifications can achieve even better results.[87] There is considerable evidence that reducing dietary salt intake lowers blood pressure, but whether this translates into a reduction in mortality and cardiovascular disease remains uncertain.[96] Estimated sodium intake ≥6g/day and <3g/day are both associated with high risk of death or major cardiovascular disease, but the association between high sodium intake and adverse outcomes is only observed in people with hypertension.[97] Consequently, in the absence of results from randomized controlled trials, the wisdom of reducing levels of dietary salt intake below 3g/day has been questioned.[96]
An abnormally fast heart rate (tachycardia) also can cause low blood pressure. The most common example of tachycardia causing low blood pressure is atrial fibrillation (Afib). Atrial fibrillation is a disorder of the heart characterized by rapid and irregular electrical discharges from the muscle of the heart causing the ventricles to contract irregularly and (usually) rapidly. The rapidly contracting ventricles do not have enough time to fill maximally with blood before each contraction, and the amount of blood that is pumped decreases in spite of the faster heart rate. Other abnormally rapid heart rhythms such as ventricular tachycardia also can produce low blood pressure, and sometimes life-threatening shock.
If your blood pressure is elevated, your doctor may request you have more readings over the course of a few days or weeks. A hypertension diagnosis is rarely given after just one reading. Your doctor needs to see evidence of a sustained problem. That’s because your environment can contribute to increased blood pressure, such as the stress you may feel by being at the doctor’s office. Also, blood pressure levels change throughout the day.
The cuff is placed around the upper arm and inflated with an air pump to a pressure that blocks the flow of blood in the main artery that travels through the arm. The arm is held at the side of the body at the level of the heart, and the pressure of the cuff is gradually released. As the pressure decreases, a health practitioner listens with a stethoscope over the artery at the front of the elbow or an electronic machine senses the pulsation. The pressure at which the practitioner (or machine) first hears a pulsation from the artery is the systolic pressure (the top number). As the cuff pressure decreases further, the pressure at which the pulsation finally stops is the diastolic pressure (the bottom number).
Postural hypotension is considered to be a failure of a person's cardiovascular system or nervous system to react appropriately to sudden changes. Usually, when a person stands up, some of their blood pools in their lower extremities. If this remains uncorrected, it would cause the person's blood pressure to fall or decrease. A person's body usually compensates by sending messages to their heart to beat faster and to their blood vessels to constrict, offsetting the drop in blood pressure. If this does not happen, or does not happen quickly enough, postural hypotension is the result.

Secondary hypertension results from an identifiable cause. Kidney disease is the most common secondary cause of hypertension.[23] Hypertension can also be caused by endocrine conditions, such as Cushing's syndrome, hyperthyroidism, hypothyroidism, acromegaly, Conn's syndrome or hyperaldosteronism, renal artery stenosis (from atherosclerosis or fibromuscular dysplasia), hyperparathyroidism, and pheochromocytoma.[23][47] Other causes of secondary hypertension include obesity, sleep apnea, pregnancy, coarctation of the aorta, excessive eating of liquorice, excessive drinking of alcohol, and certain prescription medicines, herbal remedies, and illegal drugs such as cocaine and methamphetamine.[23][48] Arsenic exposure through drinking water has been shown to correlate with elevated blood pressure.[49][50]
Recognizing heart attack symptoms and signs can help save your life or that of someone you love. Some heart attack symptoms, including left arm pain and chest pain, are well known but other, more nonspecific symptoms may be associated with a heart attack. Nausea, vomiting, malaise, indigestion, sweating, shortness of breath, and fatigue may signal a heart attack. Heart attack symptoms and signs in women may differ from those in men.

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 cause for hypertension is not always known, although it can develop as a result of other health conditions including: sleep apnea, kidney problems, and thyroid issues. Beyond chronic health conditions, risk factors for hypertension include age, the amount of salt you eat, being overweight or obese, using tobacco, drinking excessively, not exercising, and having too little potassium in your diet.

Medications used to lower blood pressure include diuretics (e.g., hydrochlorothiazide*), beta-blockers (e.g., atenolol, metoprolol), ACE inhibitors (e.g., ramipril, enalapril, lisinopril), calcium channel blockers (e.g., nifedipine, amlodipine), angiotensin II receptor blockers (e.g., losartan, valsartan), and direct renin inhibitors (e.g., aliskiren).


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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