Blood pressure normally increases with age during childhood. As in adults, higher than normal blood pressure readings in children (pediatric hypertension) is a sign of imbalance or disease. However, there are several important blood pressure issues that differ for children:

• Primary vs. secondary. In adults, nearly all cases of high blood pressure are primary (or essential) hypertension – meaning that the high blood pressure occurs on its own for no known reason. By contrast, the majority of pre-pubescent children under 10 years of age who are diagnosed with high blood pressure have secondary hypertension (high blood pressure caused by a separate underlying condition). Usually, treatment of the condition causing the hypertension leads to a return to normal blood pressure readings. Essential hypertension, however, is more common among adolescents and teenagers. This may be connected to the society-wide problem of weight gain and sedentary lifestyles among adolescents and teenagers.
  
  
• Normal ranges. In adults, there is one set of established blood pressure ranges to indicate whether readings are high, borderline, normal or low. In children, however, the measurement of blood pressure is somewhat different. Children are measured on a sliding scale using height, gender and age and compared to their peers. High blood pressure is diagnosed among children who have elevated readings relative to their peers, or who are in higher percentiles. For example, children who are in the 95th percentile (higher blood pressure than 95 percent of their peers) will be diagnosed with high blood pressure.
  
  
• Accuracy of readings. Blood pressure fluctuates normally in the course of daily life for both adults and children. However, children’s blood pressure levels may be more sensitive to stress or unfamiliar situations, such as a doctor’s visit or the blood pressure reading itself. Therefore repeated testing over time and in a variety of settings is usually necessary to the diagnosis of high blood pressure in children. In fact, the National Heart, Lung and Blood Institute recommends that high readings must be found on at least three separate occasions before a diagnosis of pediatric hypertension is made.
  
  
• Measuring blood pressure. Blood pressure measurements are taken using a stethoscope and an arm cuff (sphygmomanometer). The arm cuff used to measure blood pressure in children must be appropriate to the child’s size or the reading may not be accurate. For this same reason, home blood pressure monitoring devices designed for adults may not accurately measure blood pressure in children. Ambulatory blood pressure monitoring (ABPM) is a test in which a portable device that takes blood pressure readings regularly is worn by the patient for an extended period (usually 24 hours). While it is becoming increasingly common in adults, ABPM is not yet recommended for children.

The link between pediatric hypertension and high blood pressure in adulthood is not completely understood. It is increasingly clear, however, that hypertension among children predicts hypertension among adults. Studies have shown that children with essential hypertension, or elevated blood pressure that has no cause, are more likely to become adults with heart disease. Other studies have shown a correlation between elevated blood pressure in children and risk factors for coronary artery disease, such as calcification in the arteries and stiffness of the arterial walls. For these reasons, it is important to identify young patients with high blood pressure and treat it as early as possible.

High blood pressure can be found in children as young as newborns, but such cases are usually secondary to another condition. Recent studies have found that the average blood pressure of American adolescents and teens is on the rise, a disturbing trend that many researchers believe is connected to the increasing rate of obesity and being overweight among American children and adolescents. This is particularly worrying since past research suggests that for every 1 to 3 mm Hg (millimeters of mercury) rise in blood pressure, a child has a 10 percent increase in the risk of developing high blood pressure in adulthood.

Children with hypertensive parents are also at a greater risk of developing high blood pressure, and the risk increases further if more than one parent is hypertensive. Low birth-weight babies who gain weight rapidly may also have an increased risk for developing high blood pressure as adults.

The American Heart Association (AHA) currently recommends that children over the age of 3 receive yearly blood pressure measurements.