Imagine a garden hose hooked up to a spigot. When the hose is flexible and there are no kinks in it, you can turn on the water full blast and it will flow easily through the hose. But if there’s a kink in the hose, the water doesn’t flow as well beyond the kink. And the pressure inside the hose builds up behind the kink. Or imagine there is gunk inside the hose blocking the path of the water. Your arteries are a lot like that garden hose.
Blood pressure is assessed using two parameters -- the systolic and diastolic pressures -- which measure, respectively, the maximum pressure exerted in the arteries as the heart contracts, and the minimum pressure in those vessels between cardiac contractions. In adults, blood pressure is considered normal if the top number (systolic pressure) is between 90 and 120 and the bottom number (diastolic) is between 60 and 80.
Normal blood pressure is below 120/80. New guidelines from the American Heart Association (AHA) and the American College of Cardiology (ACC) published in November of 2017 consider blood pressure elevated between 120/80 and 129/80. High blood pressure or hypertension is now classified as stage 1 if your systolic reading falls between 130 and 139 or your diastolic reading is between 80 and 89. A measure of 140/90 or higher is now considered stage 2 hypertension. A hypertensive crisis is defined as a systolic rate over 180 or a diastolic rate above 120. An elevated blood pressure means that the heart must work harder to pump blood. High blood pressure can also damage the walls of the arteries. Over time, hypertension increases the risk of heart disease, kidney disease, and stroke. It is estimated that one in three adults in America are affected by hypertension.
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.)
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]
During relaxation of the heart (diastole), the left ventricle of the heart fills with blood returning from the lungs. The left ventricle then contracts and pumps blood into the arteries (systole). The blood pressure in the arteries during contraction of the ventricle (systolic pressure) is higher because blood is being actively ejected into the arteries. It is lower during relaxation of the ventricle (diastolic pressure) when no blood is being ejected into the arteries. The pulse we feel when we place our fingers over an artery is caused by the contraction of the left ventricle and the ejection of blood.
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.
Imagine a garden hose hooked up to a spigot. When the hose is flexible and there are no kinks in it, you can turn on the water full blast and it will flow easily through the hose. But if there’s a kink in the hose, the water doesn’t flow as well beyond the kink. And the pressure inside the hose builds up behind the kink. Or imagine there is gunk inside the hose blocking the path of the water. Your arteries are a lot like that garden hose.
With low blood pressure, the patient may feel faint or lose consciousness. This is due to lack of blood flow to the brain, and usually laying the patient supine will help them come round. This is also known as a blackout, and it could be accompanied by a dizzy feeling and light-headedness. Generally, your patient will report trouble focusing, difficulty keeping upright and lack of coordination.
Lifelong control of hypertension will minimize the risk of developing heart attack, stroke, kidney failure, blindness, and a variety of other illnesses. Unlike other illnesses in which medications are taken for only a short period of time, high blood pressure medication is usually expected to be taken for the rest of the individual's life. It is uncommon, but not rare, that significant lifestyle changes can lower blood pressure readings to normal.
Postural hypotension, or low blood pressure when a person stands up quickly, may happen to anyone for a number of reasons such as lack of food, dehydration, or simply being overly fatigued. It might also be influenced by a person's genetic make-up, medication, aging, psychological factors, dietary ones, or acute triggers such as allergy or infection. Postural hypotension happens most often in people who are taking medications to control high blood pressure or, 'hypertension.' It may also be related to strong emotions, pregnancy, diabetes, or hardening of a person's arteries. Seniors are affected by postural hypotension in particular, especially seniors who experience high blood pressure or autonomic nervous system dysfunction.
Physical examination may include listening to the heart and lungs, feeling for pulse in the wrist and ankles, and feeling and listening to the abdomen looking for signs of an enlarged aorta. The examiner may also listen in the neck for carotid bruits (sounds made by a narrowed artery in the neck) and in the abdomen for bruits made by an abdominal aortic aneurysm.
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.
Blood pressure is expressed by two measurements, the systolic and diastolic pressures, which are the maximum and minimum pressures, respectively.[1] For most adults, normal blood pressure at rest is within the range of 100–130 millimeters mercury (mmHg) systolic and 60–80 mmHg diastolic.[7][12] For most adults, high blood pressure is present if the resting blood pressure is persistently at or above 130/80 or 140/90 mmHg.[5][7] Different numbers apply to children.[13] Ambulatory blood pressure monitoring over a 24-hour period appears more accurate than office-based blood pressure measurement.[5][10]
Vasovagal reaction is a common condition in which a healthy person temporarily develops low blood pressure, slow heart rate, and sometimes fainting. A vasovagal reaction typically is brought on by emotions of fear or pain such as having blood drawn, starting an intravenous infusion, or by gastrointestinal upset. Vasovagal reactions are caused by activity of the involuntary (autonomic) nervous system, especially the vagus nerve, which releases hormones that slow the heart and widen the blood vessels. The vagus nerve also controls digestive tract function and senses activity in the digestive system. Thus, some people can have a vasovagal reaction from straining at a bowel movement or vomiting.
Blood pressure guidelines show the lower the blood pressure numbers the better. As long as no symptoms of trouble are present there is no one number that doctors consider being too low. The guidelines call for an individualized, risk-based approach to managing hypertension, as well as a personal consultation with a health care provider. While the new guidelines mean we are more aggressive about blood pressure control, lifestyle changes are always a part of the treatment plan. A treatment plan is agreed to by patient and provider, and includes ongoing communication to see how the patient is feeling and how their medications are working.
Your blood pressure is considered high when you have consistent systolic readings of 140 mm Hg or higher or diastolic readings of 90 mm Hg or higher. Based on research, your doctor may also consider you to have high blood pressure if you are an adult or child age 13 or older who has consistent systolic readings of 130 to 139 mm Hg or diastolic readings of 80 to 89 mm Hg and you have other cardiovascular risk factors.

Blood pressure fluctuates throughout the day, so measuring it in the morning might yield a different number than, say, the afternoon. Conditions like stress and lack of sleep can also fluctuate blood pressure. Visiting your doctor might feel nerve-wracking, which can elevate your blood pressure and create a condition called white coat hypertension.
Understanding the normal BP range with age can help the doctor and you to estimate your cardiovascular health. Blood pressure levels can fluctuate significantly from one reading to the next and it is important to remember that just one abnormally high reading does not signify that you have high blood pressure. Doctors usually use an average of multiple blood pressure readings taken over a period of several days to arrive at a diagnosis of high blood pressure.

Stage 1 and Stage 2 hypertensions require therapy with anti-hypertensive drugs to bring down the blood pressure. Lifestyle modifications are also necessary, but often it is not sufficient for satisfactory control of blood pressure. Hypertension is often asymptomatic in the early course of disease. Symptoms like headache, lightheadedness, palpitations and easy fatigability may occur and chances of them being present increases with increasing blood pressure.


When healthy lifestyle changes alone do not control or lower high blood pressure, your doctor may change or update your treatment plan by prescribing medicines to treat your condition. These medicines act in different ways to lower blood pressure. When prescribing medicines, your doctor will also consider their effect on other conditions you might have, such as heart disease or kidney disease. Possible high blood pressure medicines include:
One reason to visit your doctor regularly is to have your blood pressure checked. Routine checks of your blood pressure will help pick up an early rise in blood pressure, even though you might feel fine. If there's an indication that your blood pressure is high at two or more checkups, the doctor may ask you to check your blood pressure at home at different times of the day. If the pressure stays high, even when you are relaxed, the doctor may suggest exercise, changes in your diet, and, most likely, medications.
Understanding the normal BP range with age can help the doctor and you to estimate your cardiovascular health. Blood pressure levels can fluctuate significantly from one reading to the next and it is important to remember that just one abnormally high reading does not signify that you have high blood pressure. Doctors usually use an average of multiple blood pressure readings taken over a period of several days to arrive at a diagnosis of high blood pressure.
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).
Blood pressure (BP) recordings consist of two numbers. The top one is the systolic blood pressure and relates to the contraction of the left side of the heart and the peak pressure achieved when it pumps blood round the body. The bottom number is the diastolic recording and is the lowest pressure achieved in the circulation; this relates to the relaxation of the heart. Blood pressure is measured in millimetres of mercury (mmHg), e.g. 120/70 mmHg.
^ Jump up to: a b Campbell, NR; Lackland, DT; Lisheng, L; Niebylski, ML; Nilsson, PM; Zhang, XH (March 2015). "Using the Global Burden of Disease study to assist development of nation-specific fact sheets to promote prevention and control of hypertension and reduction in dietary salt: a resource from the World Hypertension League". Journal of clinical hypertension (Greenwich, Conn.). 17 (3): 165–67. doi:10.1111/jch.12479. PMID 25644474.
Although it's most common in older adults, hypertension can also affect children. The normal blood pressure for a child is dependent upon the child's age, gender, and height. Your doctor can tell if your child's blood pressure is abnormal. Children are at higher risk for hypertension if they are overweight, African-American, or if they have a family history of the condition. Children with high blood pressure may benefit from the DASH diet and taking medications. Children with high blood pressure should also maintain a healthy weight and avoid tobacco smoke.
The American Heart Association, or AHA, explains that the early symptoms of high blood pressure that people tend to think about are largely mythical. You are unlikely to notice “classic” signs such as anxiety, insomnia, or flushing in your face. You could have blood spots in your eyes due to subconjunctival hemorrhage, but dizziness itself is not among the essential symptoms of high blood pressure.
Optimal blood pressure is less than 120/80 (systolic/diastolic). In healthy people, low blood pressure without any symptoms is not usually a concern and does not need to be treated. But low blood pressure can be a sign of an underlying problem -- especially in the elderly -- where it may cause inadequate blood flow to the heart, brain, and other vital organs.
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.
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.
Orthostatic hypotension is caused by a sudden change in body position. This occurs most often when you shift from lying down to standing. This type of low blood pressure usually lasts only a few seconds or minutes. If this type of low blood pressure occurs after eating, it is called postprandial orthostatic hypotension. This type most often affects older adults, those with high blood pressure, and people with Parkinson disease.
Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017; pii: S0735-1097(17)41519-1. PMID: 29146535 www.ncbi.nlm.nih.gov/pubmed/29146535.
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