RespiteMatch.com Health Blog

It might seem odd that children can have high blood pressure, or hypertension, because we usually associate the condition with older people. But some kids do have it, even in infancy. This can be a frightening thought, because hypertension can affect not only a person’s health and lifestyle, it can also be life-threatening if left untreated.

More than 58 million people in the United States age 6 and older - or one in five people - have high blood pressure. Of those with hypertension, about one third to one half don’t even know they have it.

Hypertension isn’t as common in children as in adults (only about 1% of kids in the United States have it), but here’s the problem: there’s a common misconception that hypertension only surfaces later, in adulthood. Even most adults who have high blood pressure don’t consider that its roots might extend back to their own childhood. Nor do they think about the dangerous effects hypertension could have on their children.

From the time a child is 3 years old, regular visits to the doctor usually include a blood pressure reading. But to confirm a single elevated blood pressure level, at least two more readings must be taken on separate occasions - and this is rarely done, especially with children.

What Is Hypertension?
Hypertension is defined as blood pressure elevation that’s above the normal range, which can cause damage to the heart, brain, kidneys, and eyes. But before you can understand hypertension, you have to understand how blood pressure works.

Blood pressure changes from minute to minute, and is affected not only by activity and rest, but also by temperature, diet, emotional state, posture, and medications. But what, exactly, is blood pressure? It’s the pressure your blood exerts against your blood vessel walls as your heart pumps. The pressure is higher when your heart contracts and lower when it relaxes; but there’s always a certain amount of pressure in the arteries. That blood pressure comes from two physical forces - the heart creates one force as it pumps blood into the arteries and through the circulatory system, and the other force comes from the arteries as they resist this blood flow.

Blood pressure is measured, in millimeters of mercury (or mm Hg), using a medical instrument called a sphygmomanometer (pronounced: sfig-mo-mah-nah-muh-ter). A cuff is wrapped around the upper arm and pumped up to create pressure. When the cuff is inflated, it compresses a large artery in the arm, stopping the blood flow for a moment. Blood pressure is measured as air is gradually let out of the cuff, which allows blood to begin to flow through the artery again when the blood pressure in the artery is greater than the pressure in the cuff.

Listening with a stethoscope over the artery allows a doctor to hear the first pulse as the blood flows through - this is the systolic pressure (or the pressure at the peak of each heartbeat). The diastolic pressure (the pressure when the heart is resting between beats) is noted when the sounds disappear. When a blood pressure reading is taken, the higher number represents the systolic pressure and the lower number represents the diastolic pressure. For example: 120/80 (120 over 80) means that the systolic pressure is 120 and the diastolic pressure is 80.

Blood pressure of less than 120/80 is considered a normal reading for teens and adults. A “borderline-high” systolic pressure of 120 to 139 or a diastolic pressure of 80 to 89 needs to be closely monitored. A reading equal to or greater than 140/90 is considered “high” and should be evaluated further and probably treated.

As kids grow, their blood pressure continues to increase from a systolic pressure of about 90 in an infant to adult values in a teenager. In children, high blood pressure is defined as a blood pressure greater than the 95th percentile for their age, height, and gender (in other words, 95% of kids at the same age, height, and gender will have blood pressure below this number.)

Measurements between the 90th and 95th percentiles are considered “high-normal” or “borderline.” Children with blood pressure readings greater than the 90th percentile are three times more likely to develop high blood pressure as adults, as compared to kids with average readings. Your child’s doctor will average at least three measurements taken at different times, though, before determining whether your child has hypertension or may be at risk for getting hypertension.

It’s also important to keep in mind that blood pressure is different for everyone - for example, what would be considered normal for an adult woman would be high for a young girl.

What Causes Hypertension?
The causes of hypertension differ, depending on the age of the child. The younger the child, the more likely the hypertension will be traced to specific illnesses. In the majority of cases in preteens, the cause is kidney diseases; although other illnesses - such as blood vessel anomalies and hormonal disorders - may also be causes of hypertension. Some medications (such as steroids or oral contraceptives) may also lead to hypertension.

Even babies can have hypertension. The most common causes of hypertension in newborns are usually complications from prematurity such as a clot in the renal artery (the artery that supplies blood to the kidney) or bronchopulmonary dysplasia. Other common causes in newborns are congenital kidney abnormalities and coarctation of the aorta - a fairly common congenital defect characterized by a narrowing in part of the aorta, the major blood vessel that transports blood away from the heart.

The older the child, the more likely he or she will have what’s called essential hypertension, which is high blood pressure with no identifiable cause. Essential hypertension is found primarily in adolescents and adults. Most teens have essential hypertension for the same reasons as adults: family history, diet, stress, obesity, and lack of regular exercise. Overconsumption of alcohol and illegal drugs can also cause high blood pressure.

Getting a Diagnosis
Because there are usually no symptoms, diagnosing hypertension in children can be tricky. The most common (but still rare) symptoms are headaches, dizziness, and lightheadedness, but these usually occur only in severe hypertension and are often so mild that they’re ignored. If your child is obese and has a family history of hypertension, this should raise a red flag for essential hypertension. The only reliable way of diagnosing hypertension is with regular blood pressure measurements.

The most important thing is for parents to have their child’s blood pressure checked regularly by the pediatrician at every well-child visit or routine checkup. To try to determine the cause of hypertension, your child’s doctor may ask about your child’s medical history, eating and exercise habits (including salt intake), medication use, drinking and smoking habits, and street drug use. Urine and blood samples may also be taken to check on kidney function and blood cholesterol levels.

Treating Hypertension
Once hypertension is diagnosed, following the doctor’s recommendations is important. If an underlying illness is discovered, treating that illness may be enough to control the hypertension. On the other hand, if there’s no underlying illness, your child’s doctor may try to lower blood pressure through recommending weight loss, increased intake of fruits and vegetables, decreased salt intake, exercise, and behavior modification (such as relaxation techniques). People with hypertension should also quit or never start smoking, which can worsen the long-term cardiovascular complications of hypertension.

Most doctors prefer not to prescribe medication for children with mild hypertension. However, in cases in which lifestyle changes do not lower the child’s blood pressure, medications may be prescribed.

It’s a fallacy that physical activity should be decreased in children with high blood pressure.

Kids who have severe hypertension should not, however, participate in weight and power lifting, bodybuilding, and strength training, until their blood pressure is under control and their doctor permits them to continue.

Exercise and participation in organized sports is encouraged for all other patients whose hypertension is less severe or is well-controlled. In fact, staying fit is the key to both weight and blood pressure control. If your child is overweight, an ongoing weight-loss program monitored by your child’s doctor and a minimum of 30 minutes of aerobic exercise three to four times weekly may be recommended.

Adult hypertension often begins in childhood. Although severe hypertension is rare in kids, even mild to moderate hypertension over time can cause damage to the heart, kidneys, and blood vessels. Identifying and treating hypertension in children will help prevent this damage before it occurs.

Reviewed by: Elana Pearl Ben-Joseph, MD
Date reviewed: August 2003
Originally reviewed by: Laszlo Hopp, MD