In hypertensive emergency, there is evidence of direct damage to one or more organs.[27][28] The most affected organs include the brain, kidney, heart and lungs, producing symptoms which may include confusion, drowsiness, chest pain and breathlessness.[26] In hypertensive emergency, the blood pressure must be reduced more rapidly to stop ongoing organ damage,[26] however, there is a lack of randomized controlled trial evidence for this approach.[28]

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.

Enlarged heart. High blood pressure increases the amount of work for your heart. Like any heavily exercised muscle in your body, your heart grows bigger (enlarges) to handle the extra workload. The bigger your heart is, the more it demands oxygen-rich blood but the less able it is to maintain proper blood flow. As a result, you feel weak and tired and are not able to exercise or perform physical activities. Without treatment, your heart failure will only get worse.
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.

Being overweight increases the risk of getting hypertension and increases the workload required of your heart. Diets designed to control blood pressure are often designed to reduce calories as well. Most of these diets require decreasing consumption of fatty foods and sugars while increasing your intake of lean protein, fiber, fruits, and vegetables. A weight loss of just 10 pounds can make a significant difference in your blood pressure.

A slow heart rate (bradycardia) can decrease the amount of blood pumped by the heart. The resting heart rate for a healthy adult is between 60 and 100 beats/minute. Bradycardia (resting heart rates slower than 60 beats/minute) does not always cause low blood pressure. In fact, some highly trained athletes can have resting heart rates in the 40s and 50s (beats per minute) without any symptoms. The slow heart rates are offset by more forceful contractions of the heart that pump more blood than in non-athletes. However, in many patients bradycardia can lead to low blood pressure, lightheadedness, dizziness, and even fainting.

In November, the American Heart Association and the American College of Cardiology issued new guidelines that change how high blood pressure, or hypertension, is diagnosed. Previously, it wasn’t until an adult’s blood pressure reached 140 mmHg or higher systolic (the top, or first, number) or 90 mmHg diastolic (the bottom, or second, number) or higher that high blood pressure was diagnosed. According to the new parameters, high blood pressure should be treated at 130/80 rather than 140/90, as that is the point when our risk for heart attack, stroke, and other consequences for hypertension almost doubles.

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.
Physical changes: If something in your body changes, you may begin experiencing issues throughout your body. High blood pressure may be one of those issues. For example, it’s thought that changes in your kidney function due to aging may upset the body’s natural balance of salts and fluid. This change may cause your body’s blood pressure to increase.
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.
^ Aronow WS, Fleg JL, Pepine CJ, Artinian NT, Bakris G, Brown AS, Ferdinand KC, Ann Forciea M, Frishman WH, Jaigobin C, Kostis JB, Mancia G, Oparil S, Ortiz E, Reisin E, Rich MW, Schocken DD, Weber MA, Wesley DJ, Harrington RA, Bates ER, Bhatt DL, Bridges CR, Eisenberg MJ, Ferrari VA, Fisher JD, Gardner TJ, Gentile F, Gilson MF, Hlatky MA, Jacobs AK, Kaul S, Moliterno DJ, Mukherjee D, Rosenson RS, Stein JH, Weitz HH, Wesley DJ (2011). "ACCF/AHA 2011 expert consensus document on hypertension in the elderly: a report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents developed in collaboration with the American Academy of Neurology, American Geriatrics Society, American Society for Preventive Cardiology, American Society of Hypertension, American Society of Nephrology, Association of Black Cardiologists, and European Society of Hypertension". J Am Soc Hypertens. 5 (4): 259–352. doi:10.1016/j.jash.2011.06.001. PMID 21771565.
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]
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).                                                                                                                                                                                                
Elevated blood pressures in the medical setting may not necessarily reflect the individuals real status. "White coat hypertension" describes a patient whose blood pressure is elevated because of the stress of the visit to the doctor or other healthcare professional, and the worry that their blood pressure might be elevated. Repeated blood pressure checks at the doctor's office or the use of a home blood pressure monitoring device may be used to confirm that you have high blood pressure.

The primary symptoms of malignant hypertension is a blood pressure of 180/120 or higher and signs of organ damage. Other symptoms of malignant hypertension include bleeding and swelling of blood vessels in the retina, anxiety, nosebleeds, severe headache, and shortness of breath. Malignant hypertension may cause brain swelling, but this symptom is very rare.

Not only the degree of obesity is important, but also the manner in which the body accumulates extra fat. Some people gain weight around their belly (central obesity or "apple-shaped" people), while others store fat around their hips and thighs ("pear-shaped" people). "Apple-shaped" people tend to have greater health risks for high blood pressure than "pear-shaped" people.

There are even more medication types that can lower blood pressure. Some of these are alpha blockers, vasodilators, and central alpha agonists. Your doctor may prescribe these medications if other medications have been ineffective or if you have another condition along with hypertension. Side effects can include fast pulse, palpitations, dizziness, diarrhea, or headaches.
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.
6. Cultivate stress management. You don’t need a meta-analysis of cohort studies to prove stress can raise blood pressure, but they exist. You can’t eliminate stress, but you can minimize its impact. Research shows yoga and meditation create effective strategies to manage stress and blood pressure. If those aren’t your thing, consider other stress-relieving tactics including deep breathing or practicing mindfulness.
The first line of treatment for hypertension is lifestyle changes, including dietary changes, physical exercise, and weight loss. Though these have all been recommended in scientific advisories,[111] a Cochrane systematic review found no evidence for effects of weight loss diets on death, long-term complications or adverse events in persons with hypertension.[112] The review did find a decrease in blood pressure.[112] Their potential effectiveness is similar to and at times exceeds a single medication.[12] If hypertension is high enough to justify immediate use of medications, lifestyle changes are still recommended in conjunction with medication.
Stress reduction techniques such as biofeedback or transcendental meditation may be considered as an add-on to other treatments to reduce hypertension, but do not have evidence for preventing cardiovascular disease on their own.[125][126][127] Self-monitoring and appointment reminders might support the use of other strategies to improve blood pressure control, but need further evaluation.[128]
One especially important cause of low blood pressure is orthostatic hypotension, which is sometimes referred to as postural hypotension. This happens when blood pressure drops rapidly during changes in body position—usually when changing from sitting to standing—inducing classic signs that the blood pressure is too low, like dizziness, blurry vision, and fainting.
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).

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:

Pulmonary embolism is a condition in which a blood clot in a vein (deep vein thrombosis or DVT) breaks off and travels to the heart and eventually the lung. A large blood clot can block the flow of blood into the left ventricle from the lungs and severely diminish the blood returning to the heart for pumping. Pulmonary embolism is a life-threatening emergency.
First, we collect and analyze statewide data using telephone surveys, hospital information, and death certificates, so we are able to know which groups of people are experiencing hypertension and the impacts of uncontrolled high blood pressure. This includes looking at geography, age, racial/ethnic status, education levels, and other demographic information. When the data is compiled, we make it available on the DOH web site. We estimate that in 2015, nearly 14,000 deaths and 71,000 hospitalizations were due to heart disease and stroke.

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.