Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels and constitutes one of the principal vital signs. The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, and veins; the term blood pressure generally refers to arterial pressure, i.e., the pressure in the larger arteries, arteries being the blood vessels which take blood away from the heart.

Everyone age 3 or older should have their blood pressure checked by a healthcare provider at least once a year. Your doctor will use a blood pressure test to see if you have consistently high blood pressure readings. Even small increases in systolic blood pressure can weaken and damage your blood vessels. Your doctor will recommend heart-healthy lifestyle changes to help control your blood pressure and prevent you from developing 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.
A blood pressure reading measures both the systolic and diastolic forces, with the systolic pressure listed first. The numbers show your pressure in units of millimeters of mercury (mm Hg)—how high the pressure inside your arteries would be able to raise a column of mercury. For example, a reading of 120/80 mm Hg means a systolic pressure of 120 mm Hg and diastolic pressure of 80 mm Hg.
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.
NHLBI Expert Panel on Cardiovascular Health and Risk Reduction in Children and Adolescents. We have supported the development of guidelines based on up-to-date research to evaluate and manage risk of heart disease in children and adolescents, including high blood pressure. Visit Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents for more information.
Low blood pressure is diagnosed by a doctor when they check your blood pressure with a sphygmomanometer. For people who experience low blood pressure without other symptoms, it may only require regular monitoring by a doctor during routine exams, and medical treatment may not be necessary. If certain signs suggest an underlying condition, your doctor may recommend one or more of the following tests to diagnose a cause for your hypotension:
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.
Medications such as calcium channel blockers, beta blockers, and digoxin (Lanoxin) can slow the rate at which the heart contracts. Some elderly people are extremely sensitive to these medications since they are more likely to have diseased hearts and electrical conduction tissues. In some individuals, the heart rate can become dangerously slow even with small doses of these medications.

Chronic low blood pressure with no symptoms is almost never serious. But health problems can occur when blood pressure drops suddenly and the brain is deprived of an adequate blood supply. This can lead to dizziness or lightheadedness. Sudden drops in blood pressure most commonly occur in someone who's rising from a lying down or sitting position to standing. This kind of low blood pressure is known as postural hypotension or orthostatic hypotension. Another type of low blood pressure can occur when someone stands for a long period of time. This is called neurally mediated hypotension. When it leads to passing out, if is called vasovagal syncope.
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.)
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.
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.
Genetics plays a role in hypertension, and much of essential hypertension could ultimately turn out to be genetic in origin. Genes are believed to have approximately 30 percent to 50 percent impact on blood pressure. Specific genes have not been identified as responsible for hypertension, however. This may be due to the fact that there are many genes that interact together to influence blood pressure, with some of these genetic variants being more common than others.
Hypertension is diagnosed on the basis of a persistently high resting blood pressure. The American Heart Association recommends at least three resting measurements on at least two separate health care visits.[74] The UK National Institute for Health and Care Excellence recommends ambulatory blood pressure monitoring to confirm the diagnosis of hypertension if a clinic blood pressure is 140/90 mmHg or higher.[75]