Your doctor may also use a device called an ophthalmoscope to look at the blood vessels in your eyes. Doctors can see if these vessels have thickened, narrowed, or burst, which may be a sign of high blood pressure. Your doctor will also use a stethoscope to listen to your heart and the sound of blood flowing through your arteries. In some cases, a chest x-ray and electrocardiogram may be needed.
Exercise also causes vasodilation, or the widening of blood vessels, which increases blood flow and decreases peripheral resistance — which, in healthy people, keeps the diastolic blood pressure from rising during activity. In fact, a diastolic blood pressure increasing greater than 10 mmHg during or after exercise represents an unstable form of hypertension, and may be associated with coronary artery disease, notes Len Kravitz, Ph.D. of the University of New Mexico.

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.
Pulse pressure (the difference between systolic and diastolic blood pressure) is frequently increased in older people with hypertension. This can mean that systolic pressure is abnormally high, but diastolic pressure may be normal or low a condition termed isolated systolic hypertension.[59] The high pulse pressure in elderly people with hypertension or isolated systolic hypertension is explained by increased arterial stiffness, which typically accompanies aging and may be exacerbated by high blood pressure.[60]
Normal blood pressure is less than 120/80. Knowing your blood pressure and remembering to check it regularly can help save your life. Choosing healthier, heart-conscious foods, maintaining a healthy weight, getting up and staying active, and managing your stress are great ways to help keep your blood pressure at the level it should be. Learn more about what you can do to help control your blood pressure.
Right after exercise is stopped, blood pressure decreases — often to levels a bit lower than normal resting blood pressure, and this effect can last for hours. Also, people who exercise regularly usually experience permanent improvements in resting blood pressure levels, as exercise strengthens the heart, helps with weight loss, improves circulation and lessens peripheral resistance — all factors that benefit blood pressure.

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.
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.
Although the guidelines do not change the traditional definition of high blood pressure, they do call for more aggressive treatment of the condition through the use of a combination of blood-pressure lowering medications. In fact, they say that most people with high blood pressure will require two or more drugs to achieve a blood pressure goal of less than 140/90. The blood pressure goal in people with diabetes or kidney disease should be less than 130/80.

Palma Gamiz JL, et al. Iberian Multicenter Imidapril Study on Hypertension: A twelve-week, Multicenter, Randomized, Double-blind, Parallel-Group, Noninferiority Trial of the Antihypertensive Efficacy and Tolerability of Imidapril and Candesartan in Adult Patients With Mild to Moderate Essential Hypertension: the Iberian Multicenter Imidapril Study on Hypertension (IMISH).
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).                                                                                                                                                                                                
In Europe hypertension occurs in about 30-45% of people as of 2013.[12] In 1995 it was estimated that 43 million people (24% of the population) in the United States had hypertension or were taking antihypertensive medication.[141] By 2004 this had increased to 29%[142][143] and further to 32% (76 million US adults) by 2017.[7] In 2017, with the change in definitions for hypertension, 46% of people in the United States are affected.[7] African-American adults in the United States have among the highest rates of hypertension in the world at 44%.[144] It is also more common in Filipino Americans and less common in US whites and Mexican Americans.[6][145] Differences in hypertension rates are multifactorial and under study.[146]
The drug of choice for hypertensive, pregnant women is one of the oldest high blood pressure medications on the market. Methyldopa, which works to lower blood pressure through the central nervous system, has the lowest risk of harming the mother and developing fetus. Other possible safe options include labetalol, beta blockers, and diuretics. Two classes of drugs which should never be used during pregnancy include the ACE inhibitors and the angiotensin II receptor blockers.
On physical examination, hypertension may be associated with the presence of changes in the optic fundus seen by ophthalmoscopy.[22] The severity of the changes typical of hypertensive retinopathy is graded from I to IV; grades I and II may be difficult to differentiate.[22] The severity of the retinopathy correlates roughly with the duration or the severity of the hypertension.[20]