Blood pressure is expressed by two measurements, the systolic and diastolic pressures, which are the maximum and minimum pressures, respectively. For most adults, normal blood pressure at rest is within the range of 100–130 millimeters mercury (mmHg) systolic and 60–80 mmHg diastolic. For most adults, high blood pressure is present if the resting blood pressure is persistently at or above 130/80 or 140/90 mmHg. Different numbers apply to children. Ambulatory blood pressure monitoring over a 24-hour period appears more accurate than office-based blood pressure measurement.
For older people, often the first number (systolic) is 130 or higher, but the second number (diastolic) is less than 80. This problem is called isolated systolic hypertension, which is due to age-related stiffening of the major arteries. It is the most common form of high blood pressure in older people and can lead to serious health problems (stroke, heart disease, eye problems, and kidney failure) in addition to shortness of breath during light physical activity, lightheadedness upon standing too fast, and falls. Isolated systolic hypertension is treated in the same way as regular high blood pressure (130 or higher for the first number, or 80 or higher for the second number) but may require more than one type of blood pressure medication. If your doctor determines that your systolic pressure is above a normal level for your age, ask how you can lower it.
Much of the disease burden of high blood pressure is experienced by people who are not labeled as hypertensive. Consequently, population strategies are required to reduce the consequences of high blood pressure and reduce the need for antihypertensive medications. Lifestyle changes are recommended to lower blood pressure, before starting medications. The 2004 British Hypertension Society guidelines proposed lifestyle changes consistent with those outlined by the US National High BP Education Program in 2002 for the primary prevention of hypertension:
Anaphylaxis (anaphylactic shock) is a potentially fatal allergic reaction to medications such as penicillin, intravenous iodine used in some X-ray studies, foods such as peanuts, or bee stings (insect stings). In addition to a severe drop in blood pressure, individuals may also experience hives and wheezing due to constriction of the airways, and a swollen throat, which causes difficulty breathing. The shock is caused by enlargement of blood-containing blood vessels and escape of water from the blood into the tissues.
Researchers at the University of Melbourne and Macquarie University have uncovered unusual activity between neurons controlling breathing and blood pressure during the development of essential hypertension. Essential hypertension, which is high blood pressure with no known cause, affects 30% of the global population and is a major contributor to cardiovascular disease.
The guidelines also outline very clearly when a diet-and-lifestyle approach is the recommended, first-line treatment, and when medications are simply just what you have to do. Thankfully, the decision is largely based on facts and statistics. For the elevated blood pressure category, medications are actually not recommended; rather, a long list of evidence-based, non-drug interventions are. What are these interventions? Things that really work: a diet high in fruits and vegetables (such as the DASH diet, which is naturally high in potassium); decreased salt and bad fats; more activity; weight loss if one is overweight or obese; and no more than two alcoholic drinks per day for men, and one for women. Simply changing what you eat can bring down systolic blood pressure by as much as 11 points, and each additional healthy habit you adopt can bring it down another four to five points.
Unchecked, high blood pressure can lead to a myriad of serious health problems, such as heart attacks, strokes, and other forms of heart disease and kidney disease. It is extremely dangerous during pregnancy because it contributes to devastating and even deadly problems for moms and babies. Other impacts of hypertension include vision problems and sexual dysfunction.
For an accurate diagnosis of hypertension to be made, it is essential for proper blood pressure measurement technique to be used. Improper measurement of blood pressure is common and can change the blood pressure reading by up to 10 mmHg, which can lead to misdiagnosis and misclassification of hypertension. Correct blood pressure measurement technique involves several steps. Proper blood pressure measurement requires the person whose blood pressure is being measured to sit quietly for at least five minutes which is then followed by application of a properly fitted blood pressure cuff to a bare upper arm. The person should be seated with their back supported, feet flat on the floor, and with their legs uncrossed. The person whose blood pressure is being measured should avoid talking or moving during this process. The arm being measured should be supported on a flat surface at the level of the heart. Blood pressure measurement should be done in a quiet room so the medical professional checking the blood pressure can hear the Korotkoff sounds while listening to the brachial artery with a stethoscope for accurate blood pressure measurements. The blood pressure cuff should be deflated slowly (2-3 mmHg per second) while listening for the Korotkoff sounds. The bladder should be emptied before a person's blood pressure is measured since this can increase blood pressure by up to 15/10 mmHg. Multiple blood pressure readings (at least two) spaced 1–2 minutes apart should be obtained to ensure accuracy. Ambulatory blood pressure monitoring over 12 to 24 hours is the most accurate method to confirm the diagnosis.
Systolic BP lower than 90 mm Hg or diastolic BP lower than 60 mm Hg is considered low blood pressure or hypotension. Unlike hypertension, hypotension is more likely to be due to a primary cause (dehydration, heart disease, drugs, endocrine disease, etc.) and thus therapy is often aimed at treating the primary cause. Borderline BP with no obvious cause can be treated with increased salt and water intake, regular mild exercises, cutting down on alcohol, etc.). Drug therapy can be used if such hypotension is not amenable to these measures.
Adrenal insufficiency, for example, due to Addison's disease, can cause low blood pressure. Addison's disease is a disorder in which the adrenal glands (small glands next to the kidneys) are destroyed. The destroyed adrenal glands can no longer produce sufficient adrenal hormones (specifically cortisol) necessary to maintain normal bodily functions. Cortisol has many functions, one of which is to maintain blood pressure and the function of the heart. Addison's disease is characterized by weight loss, muscle weakness, fatigue, low blood pressure, and, sometimes, darkening of the skin.
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.
Blood pressure readings fall into four general categories, ranging from normal to stage 2 high blood pressure (hypertension). The level of your blood pressure determines what kind of treatment you may need. To get an accurate blood pressure measurement, your doctor should evaluate your readings based on the average of two or more blood pressure readings at three or more office visits.