As mentioned earlier, blood pressure increases with age, beginning from infancy to older adulthood. Since most healthy babies and children are typically not at risk for blood pressure problems, most doctors do not check their blood pressure routinely. But, the normal BP range for all adults, regardless of their age, is considered to be lesser than 120/80.

Moderate or severe bleeding can quickly deplete an individual's body of blood, leading to low blood pressure or orthostatic hypotension. Bleeding can result from trauma, surgical complications, or from gastrointestinal abnormalities such as ulcers, tumors, or diverticulosis. Occasionally, the bleeding may be so severe and rapid (for example, bleeding from a ruptured aortic aneurysm) that it causes shock and death rapidly.
Recent updates to guidelines from the American Heart Association and the American College of Cardiology changed the definition of high blood pressure or hypertension for most people. High blood pressure is now generally defined as 130 or higher for the first number, or 80 or higher for the second number (previously it was 140/90). However, there are important considerations for older adults in deciding whether to start treatment for high blood pressure, including other health conditions and overall fitness. If your blood pressure is above 130/80, your doctor will evaluate your health to determine what treatment is needed to balance risks and benefits in your particular situation.
Blood pressure monitors for use at home can be bought at drug stores, department stores, and other places. Again, these monitors may not always give you a correct reading. You should always compare your machine’s reading with a reading from your doctor’s machine to make sure they are the same. Remember that any measurement above normal should prompt a visit to the doctor, who can then talk with you about the best course of action.
A number of medications contribute to heart disease, including corticosteroids, oral contraceptives, some decongestants, medications that contain caffeine, and many others. In general, it is best to check the label to see if hypertension is one of the side effects of any medications you take, especially if you already have hypertension or if you are at increased risk for it.

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.

^ 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.

How the heart pumps blood into the arteries with enough force to push blood to the far reaches of each organ from the top of the head to the bottom of the feet. Blood pressure can be defined as the pressure of blood on the walls of the arteries as it circulates through the body. Blood pressure is highest as its leaves the heart through the aorta and gradually decreases as it enters smaller and smaller blood vessels (arteries, arterioles, and capillaries). Blood returns in the veins leading to the heart, aided by gravity and muscle contraction.
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.
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).                                                                                                                                                                                                
Dietary changes can help control blood pressure. One diet designed to promote lower blood pressure is known as the DASH diet. This stands for Dietary Approaches to Stop Hypertension. The DASH diet recommends eating more vegetables, fruits, whole grains, low-fat dairy products, poultry, nuts, and fish. Red meat, saturated fats, and sweets should be avoided. The DASH diet can lower blood pressure within 2 weeks. It can also help to reduce your intake of sodium. The following is the DASH diet suggested daily intake:
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.

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.

Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated.[10] High blood pressure typically does not cause symptoms.[1] Long-term high blood pressure, however, is a major risk factor for coronary artery disease, stroke, heart failure, atrial fibrillation, peripheral vascular disease, vision loss, chronic kidney disease, and dementia.[2][3][4][11]
Hypertension results from a complex interaction of genes and environmental factors. Numerous common genetic variants with small effects on blood pressure have been identified[34] as well as some rare genetic variants with large effects on blood pressure.[35] Also, genome-wide association studies (GWAS) have identified 35 genetic loci related to blood pressure; 12 of these genetic loci influencing blood pressure were newly found.[36] Sentinel SNP for each new genetic locus identified has shown an association with DNA methylation at multiple nearby CpG sites. These sentinel SNP are located within genes related to vascular smooth muscle and renal function. DNA methylation might affect in some way linking common genetic variation to multiple phenotypes even though mechanisms underlying these associations are not understood. Single variant test performed in this study for the 35 sentinel SNP (known and new) showed that genetic variants singly or in aggregate contribute to risk of clinical phenotypes related to high blood pressure.[36] 

When your heart contracts and squeezes blood out into your network of arteries, the pressure inside those blood vessels is at its highest. This is called systolic pressure and it’s the top number on your blood pressure reading. In between beats, the heart relaxes and the pressure drops. This is your diastolic blood pressure, and it’s the reading’s bottom number.

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.

Recent updates to guidelines from the American Heart Association and the American College of Cardiology changed the definition of high blood pressure or hypertension for most people. High blood pressure is now generally defined as 130 or higher for the first number, or 80 or higher for the second number (previously it was 140/90). However, there are important considerations for older adults in deciding whether to start treatment for high blood pressure, including other health conditions and overall fitness. If your blood pressure is above 130/80, your doctor will evaluate your health to determine what treatment is needed to balance risks and benefits in your particular situation.
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]
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.
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] 

^ Jump up to: a b Kato, Norihiro; Loh, Marie; Takeuchi, Fumihiko; Verweij, Niek; Wang, Xu; Zhang, Weihua; Kelly, Tanika N.; Saleheen, Danish; Lehne, Benjamin (2015-11-01). "Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation". Nature Genetics. 47 (11): 1282–93. doi:10.1038/ng.3405. ISSN 1546-1718. PMC 4719169. PMID 26390057.
If dehydration contributes to the problem, increased fluid intake would be needed based in part on your body mass index (BMI). For example, a person with a normal BMI would likely only need eight to ten 8-ounce glasses of water per day to maintain ideal hydration. People with a high BMI may need far more. Adding more salt to your diet may also aid in normalizing your 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.

Hypertension is rarely accompanied by symptoms, and its identification is usually through screening, or when seeking healthcare for an unrelated problem. Some people with high blood pressure report headaches (particularly at the back of the head and in the morning), as well as lightheadedness, vertigo, tinnitus (buzzing or hissing in the ears), altered vision or fainting episodes.[20] These symptoms, however, might be related to associated anxiety rather than the high blood pressure itself.[21]
Excellent point! I can’t speak for anyone specifically, but I can say that generally, doctors make the worst patients. We don’t always follow the textbook guidelines nor abide by health recommendations. Then, there’s genetics, a pretty powerful force, and one over which we have little control. And, of course, there is just plain bad luck (or fate, finger of God, however you choose to describe it). So, many factors can come into play when a doctor gets diagnosed with what can otherwise be considered a preventable disease.

As for when to check your blood pressure, the most important thing is to do it consistently the same time of the day (ask the doctor which time he prefers and also what time in relation to taking your medication). The following article has a lot of good information for someone just starting to monitor their blood pressure:

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.
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.
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!
Most doctors do not make a final diagnosis of high blood pressure until they measure your blood pressure several times (at least 2 blood pressure readings on 3 different days). Some doctors ask their patients to wear a portable machine that measures their blood pressure over the course of several days. This machine may help the doctor find out whether a patient has true high blood pressure or what is known as “white-coat hypertension.” White-coat hypertension is a condition in which a patient’s blood pressure rises during a visit to a doctor when anxiety and stress probably play a role.

Most commonly high blood pressure causes no symptoms at all. This means that people with high blood pressure can be having damage occur to their heart, kidneys, eyes, and circulation without feeling badly! It is very important, therefore, to have blood pressure testing as part of the routine physical examination. However, in people with uncomplicated high blood pressure, they may experience
Hypertension in African-Americans tends to occur earlier in life and tends to be more severe. Plus, some medications that work to lower blood pressure in other ethnicities may have limited effect on African-Americans. Thiazide diuretics (such as HCTZ) or a calcium channel blocker are recommended first choices along with the possible add-on of a second drug from either the ACE inhibitor class or the angiotensin II receptor blocker group.
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.
ACE (angiotensin converting enzyme) inhibitors are another class of antihypertensive drugs. They reduce the body's levels of angiotensin II, a substance that narrows blood vessels. This means that arteries are more open (dilated) and the blood pressure is lower. ACE inhibitors can be used alone, or with other medications such as diuretics. Side effects of ACE inhibitors can include skin rash, dry cough, dizziness, and elevated potassium levels. Women who are pregnant, planning to get pregnant, or breastfeeding should not take ACE inhibitors.
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.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Quitting smoking. Visit Smoking and Your Heart and the National Heart, Lung, and Blood Institute’s Your Guide to a Healthy Heart [PDF – 2MB]. Although these resources focus on heart health, they include basic information about how to quit smoking. For free help and support to quit smoking, you can call the National Cancer Institute’s Smoking Quitline at 1-877-44U-QUIT (1-877-448-7848).
James, P.A., Oparil, S., Carter, B.L., Cushman, W.C., Dennison-Himmelfarb, C., Handler, J., & Ortiz, E. (2013, December 18). 2014 evidence-based guideline for the management of high blood pressure in adults: Report from the panel members appointed to the eighth joint national committee. Journal of the American Medical Association. Retrieved from

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).
If your blood pressure is always on the low side and you do not have any of the above symptoms, there is usually no cause for concern. Similarly, if you have a single at-home blood pressure reading that is abnormally low without any symptoms, you probably do not need to see your doctor. It is normal for your blood pressure to rise and fall over time, and your body is usually able to get your blood pressure back to normal.
A person consistently showing blood pressure higher than 140/90 over several readings is considered to have hypertension. Doctors advise these people to make effective lifestyle changes to help lower their blood pressure, such as maintaining a healthy weight, including exercise in their daily routine, limiting salt and alcohol intake, and quitting smoking. The doctors will also recommend medication for hypertension depending on how much higher the BP is as compared to the normal blood pressure range and any other health problems that the patient faces.