Blood pressure changes throughout the day and varies from person to person. Various factors affect blood pressure, including your body position, breathing rhythm, stress level, physical activity, medications, what you eat or drink, and the time of the day (blood pressure is usually lowest at night when you sleep and rises when you wake up). In healthy individuals, your body responds and adapts to these changes to keep your blood pressure within a normal range. This ensures that vital organs, such as your brain and kidneys, receive a constant blood flow and nutrient supply.
Some people have low blood pressure all the time. They have no symptoms and their low readings are normal for them. In other people, blood pressure drops below normal because of a medical condition or certain medicines. Some people may have symptoms of low blood pressure when standing up too quickly. Low blood pressure is a problem only if it causes dizziness, fainting or in extreme cases, shock.
Low blood pressure is also known as hypotension. This is usually defined in an adult as a systolic recording of less than 90 mmHg, although it has been suggested that for elderly people, below 110 mmHg is a more appropriate definition. Blood pressure and heart rate are controlled by the autonomic nervous system (the nervous system that controls bodily functions that we do not have to think about).                                                                                                                                                                                                
The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the Nation’s biomedical research agency that makes important scientific discovery to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders, including high blood pressure. Learn about the current and future NHLBI efforts to improve health through research and scientific discovery.

You are considered to have hypertension if your systolic blood pressure measurements are between 130 and 139 or your diastolic measurement falls between 80 and 89. At this level of blood pressure you may not have any symptoms. When blood pressure reaches 180/120 or higher, a serious condition known as a malignant hypertension or hypertension crisis may occur. This can lead to stroke, kidney damage, heart attacks, or loss of consciousness. If you measure your blood pressure and it is this high, rest a few minutes and measure again. If it remains high, call 911.


As you age, prevention becomes even more important. Systolic pressure tends to creep up once you’re older than 50, and it’s far more important in predicting the risk of coronary heart disease and other conditions. Certain health conditions, such as diabetes and kidney disease, may also play a role. Talk to your doctor about how you can manage your overall health to help prevent the onset of hypertension.

^ 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.

Anyone can develop hypotension, but certain groups of people are more likely to experience it, and there are different types. For instance, orthostatic (positional) hypotension, which occurs when you stand up after sitting or lying down, is more common in older adults. Typically, “your body has certain compensatory mechanisms to prevent your blood pressure from falling when you stand up,” explains Willie Lawrence, MD, an interventional cardiologist at Research Medical Center in Kansas City, Missouri, and a spokesperson for the American Heart Association. But, he adds, “orthostatic hypotension is a problem for some people because these reflexes that should occur, don’t occur.”
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.
You will work with your provider to come up with a treatment plan. It may include only the lifestyle changes. These changes, such as heart-healthy eating and exercise, can be very effective. But sometimes the changes do not control or lower your high blood pressure. Then you may need to take medicine. There are different types of blood pressure medicines. Some people need to take more than one type.
^ Roerecke, Michael; Tobe, Sheldon W.; Kaczorowski, Janusz; Bacon, Simon L.; Vafaei, Afshin; Hasan, Omer S. M.; Krishnan, Rohin J.; Raifu, Amidu O.; Rehm, Jürgen (27 June 2018). "Sex‐Specific Associations Between Alcohol Consumption and Incidence of Hypertension: A Systematic Review and Meta‐Analysis of Cohort Studies". Journal of the American Heart Association. 7 (13): e008202. doi:10.1161/JAHA.117.008202.
Lynda is a registered nurse with three years experience on a busy surgical floor in a city hospital. She graduated with an Associates degree in Nursing from Mercyhurst College Northeast in 2007 and lives in Erie, Pennsylvania in the United States. In her work, she took care of patients post operatively from open heart surgery, immediately post-operatively from gastric bypass, gastric banding surgery and post abdominal surgery. She also dealt with patient populations that experienced active chest pain, congestive heart failure, end stage renal disease, uncontrolled diabetes and a variety of other chronic, mental and surgical conditions. Her Website.
African-Americans tend to develop hypertension earlier in life and often experience more severe blood pressure elevation. It is not known for sure why high blood pressure is more common in this group, but researchers theorize it may include higher rates of obesity and diabetes among African-Americans and a gene that makes African-Americans more sensitive to salt. In people who have this gene, even just one-half teaspoon of salt could elevate blood pressure as much as 5 mmHg. (5)
Obesity: As body weight increases, the blood pressure rises. Obesity is defined as having a body mass index (BMI) greater than 30 kg/m. A BMI of 25-30 kg/m is considered overweight (BMI=weight in pounds x 703/ height in inches). Being overweight increases the risk of high blood pressure. Healthcare professionals recommend that all individuals who are obese and have high blood pressure lose weight until they are within 15% of their healthy body weight.
^ Xie, X; Atkins, E; Lv, J; Bennett, A; Neal, B; Ninomiya, T; Woodward, M; MacMahon, S; Turnbull, F; Hillis, GS; Chalmers, J; Mant, J; Salam, A; Rahimi, K; Perkovic, V; Rodgers, A (30 January 2016). "Effects of intensive blood pressure lowering on cardiovascular and renal outcomes: updated systematic review and meta-analysis". Lancet. 387 (10017): 435–43. doi:10.1016/S0140-6736(15)00805-3. PMID 26559744.
Sodium is a key part of how the body controls blood pressure levels. The kidneys help balance fluid and sodium levels in the body. They use sodium and potassium to remove excess fluid from the blood. The body gets rid of this excess fluid as urine. When sodium levels in the blood are high, blood vessels retain more fluid. This increases blood pressure against the blood vessel walls. 

^ Sacks, F. M.; Svetkey, L. P.; Vollmer, W. M.; Appel, L. J.; Bray, G. A.; Harsha, D.; Obarzanek, E.; Conlin, P. R.; Miller, E. R. (2001-01-04). "Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group". The New England Journal of Medicine. 344 (1): 3–10. doi:10.1056/NEJM200101043440101. ISSN 0028-4793. PMID 11136953.
Dietary changes: The health care provider might recommend a diet that includes more vegetables (especially leafy green vegetables), fruits, low-fat dairy products, and fiber-rich foods, and fewer carbohydrates, fats, processed foods, and sugary drinks. He or she also might recommend preparing low-sodium dishes and not adding salt to foods. Watch out for foods with lots of hidden salt (like bread, sandwiches, pizza, and many restaurant and fast-food options). 

Drinking too much alcohol is a risk factor for high blood pressure. The American Heart Association guidelines recommend the consumption of no more than two alcoholic drinks per day for men and no more than one drink a day for women. One drink is defined as one 12-ounce beer, 4 ounces of wine, 1.5 ounces of 80-proof spirits, or 1 ounce of 100-proof spirits. Adults who consume more than three drinks in one sitting temporarily increase their blood pressure. However, binge drinking can lead to long-term increased blood pressure.
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).
Your doctor may suggest that you check your blood pressure at home. The easiest way to do this is to use a digital blood pressure monitor. You can get a monitor from your local drug store, hospital, clinic or online. Your doctor can help you find a monitor that is right for you and show you how to use it. Many pharmacies and grocery stores also have in-store monitors that you can use for free.
Unlike high blood pressure symptoms, which are poorly defined and often totally absent, low blood pressure symptoms tend to be more upfront and easily recognizable. The development of symptoms is often a warning sign of a potentially serious underlying disorder. Generally speaking, your blood pressure would need to fall pretty dramatically before symptoms develop.

Bahar Gholipour is a staff reporter for Live Science covering neuroscience, odd medical cases and all things health. She holds a Master of Science degree in neuroscience from the École Normale Supérieure (ENS) in Paris, and has done graduate-level work in science journalism at the State University of New York at Stony Brook. She has worked as a research assistant at the Laboratoire de Neurosciences Cognitives at ENS.
The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the Nation’s biomedical research agency that makes important scientific discovery to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders, including high blood pressure. Learn about the current and future NHLBI efforts to improve health through research and scientific discovery.
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.

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.
Hypertensive Crisis This is an occurrence of high blood pressure that requires medical attention. If you have a blood pressure reading of 180/120 mm Hg, wait five minutes and test again. If it is consistently this high, contact your doctor immediately. If blood pressure is higher than 180/120 mm Hg and you are experiencing chest pain, shortness of breath, back pain, numbness and weakness, change in vision, and difficulty speaking, you may have organ damage and should call 911. (4)
It has been shown that meditation and other relaxation techniques can help lower blood pressure. Yoga, tai chi, and breathing exercises can also help reduce blood pressure. It's best when these are combined with changes in diet and exercise. Tell your doctor if you are taking any herbal remedies, since some of these preparations can actually raise blood pressure or interact with your blood pressure medications. The following are supplements that may lower blood pressure:
High blood pressure is classified as either primary (essential) high blood pressure or secondary high blood pressure.[5] About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors.[5][6] Lifestyle factors that increase the risk include excess salt in the diet, excess body weight, smoking, and alcohol use.[1][5] The remaining 5–10% of cases are categorized as secondary high blood pressure, defined as high blood pressure due to an identifiable cause, such as chronic kidney disease, narrowing of the kidney arteries, an endocrine disorder, or the use of birth control pills.[5]
^ 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.
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