Unlike high blood pressure, low blood pressure is defined primarily by signs and symptoms of low blood flow and not by a specific blood pressure number. Some individuals routinely may have blood pressure numbers of 90/50 with no symptoms and therefore do not have low blood pressure. However, others who normally have higher blood pressures may develop symptoms of low blood pressure if their blood pressure drops to 100/60.
"The implications and potential benefits of such healthier lifestyles could be great, particularly since about 22% of the adult population falls into the prehypertensive category," says Chobanian, who is also dean of the Boston University School of Medicine. "In fact, the blood pressure effects of weight reduction or adoption of the DASH eating plan can be comparable to those achieved with any single blood pressure medication."
The value of routine screening for hypertension in children over the age of 3 years is debated.[90][91] In 2004 the National High Blood Pressure Education Program recommended that children aged 3 years and older have blood pressure measurement at least once at every health care visit[89] and the National Heart, Lung, and Blood Institute and American Academy of Pediatrics made a similar recommendation.[92] However, the American Academy of Family Physicians[93] supports the view of the U.S. Preventive Services Task Force that the available evidence is insufficient to determine the balance of benefits and harms of screening for hypertension in children and adolescents who do not have symptoms.[94]
^ Jump up to: a b Campbell, NR; Lackland, DT; Lisheng, L; Niebylski, ML; Nilsson, PM; Zhang, XH (March 2015). "Using the Global Burden of Disease study to assist development of nation-specific fact sheets to promote prevention and control of hypertension and reduction in dietary salt: a resource from the World Hypertension League". Journal of clinical hypertension (Greenwich, Conn.). 17 (3): 165–67. doi:10.1111/jch.12479. PMID 25644474.
If your systolic and diastolic blood pressure are in two different categories, doctors consider the number that is in the higher category. For example, if your blood pressure is 135/91, your systolic blood pressure is in the prehypertensive range and your diastolic blood pressure is in the range of Stage 1 hypertension. Your measurement or 135/91 would place you in the category of Stage 1 hypertension.
Medicines are available if these changes do not help control your blood pressure within 3 to 6 months. Diuretics help rid your body of water and sodium. ACE inhibitors block the enzyme that raises your blood pressure. Other types of medicines— beta blockers, calcium channel blockers, and other vasodilators—work in different ways, but their overall effect is to help relax and widen your blood vessels and reduce the pressure inside the vessel. [See also the free government publication “Medicines to Help You: High Blood Pressure” (PDF) from the US Food and Drug Administration.]
Blood pressure control is a lifelong challenge. Hypertension can progress through the years, and treatments that worked earlier in life may need to be adjusted over time. Blood pressure control may involve gradually making lifestyle changes like diet, weight loss, exercise, and possibly taking medicine if necessary. In some situations, medications may be recommended immediately. As with many diseases, you and your doctor should work together to find the treatment plan that works for you.
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.

Peter, I’ve been using a blood pressure meter for nearly 30 years, so my response is based on my personal experience and information I’ve acquired over the years. First, I suggest that you take your meter to the doctor and have them check several readings of your meter against theirs. For example, If your meter consistently shows it’s 10 points lower than the doctor’s, just delete the 10 points from your meter reading (have them check both numbers so you can adjust both as necessary). Also, it’s common that many doctor’s offices take your blood pressure incorrectly (you should actually sit still for 5 minutes, with your feet on the floor and the cuff at the same level as your heart) . Some of us have”white coat” hypertension, so you may always be elevated at the doctor’s office. If you are a large man, you (and your doctor’s office) may need to use a larger cuff as the wrong size of cuff can affect your reading. Also, I spoke with customer service at one of the companies that makes many of the home & professional meters, and she told me that the automated machines are not very accurate if you have kidney disease or heart failure (I have both). Ask the doctor’s staff to always use the manual system and it will be more accurate than those noisy automatic ones.

Keeping track of your blood pressure is important. Your doctor can help you learn how to check your blood pressure at home. Each time you check your own blood pressure, record your numbers and the date. Send or take the log of your blood pressure readings with you for appointments with your doctor. Return to Screening for reminders on how to prepare for blood pressure testing.
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.

Factors that increase your blood pressure can cause elevated levels. Medications such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers, and some prescription drugs may cause a temporary rise in blood pressure. The buildup of fatty deposits in the arteries (atherosclerosis) can also lead to prehypertension. Other conditions that may lead to prehypertension include the following:

There is no treatment available for the causes of portal hypertension. However, treatment can prevent or manage the complications. Diet, medication (nonselective beta-blockers), endoscopic therapy, surgery, and radiology procedures can all help in treating or preventing symptoms of portal hypertension. If these treatments are unsuccessful in treating symptoms, transjugular intrahepatic portosystemic shunt (TIPS) or distal splenorenal shunt (DSRA) are two procedures that may reduce pressure in the portal veins. Maintaining a healthy lifestyle may help to prevent portal hypertension.