What is blood pressure?
High blood pressure is also called hypertension. Blood pressure, measured with a blood pressure cuff and stethoscope by a nurse or other healthcare provider, is the force of the blood pushing against the artery walls.
Two numbers are recorded when measuring blood pressure:
- The higher number, or systolic pressure, refers to the pressure inside the artery when the heart contracts and pumps blood through the body.
- The lower number, or diastolic pressure, refers to the pressure inside the artery when the heart is at rest and is filling with blood.
Each time the heart beats, it pumps blood into the arteries, resulting in the highest blood pressure as the heart contracts. Both the systolic and diastolic pressures are recorded as mm Hg (millimeters of mercury). This recording represents how high the mercury column is raised by the pressure of the blood.
What is high blood pressure?
High blood pressure means that there is higher than normal pressure inside the arteries either during systole (when the heart contracts and pumps blood through the body), or during diastole (when the heart is at rest and is filling with blood.
- If the pressure is high during the pumping phase (systole), then the first number recorded with a blood pressure reading (the systolic pressure) will be high.
- If the pressure is high during the resting period (diastole), then the second number recorded (the diastolic pressure) will be high.
When is the blood pressure too high?
Blood pressures vary depending on the age of your child, as well as according to height and weight, and the gender of your child. Generally, blood pressure is low in infancy, and rises slowly as children age. Boys' blood pressures are slightly higher than girls' are, and taller people generally have higher blood pressures than short people do.
For example, an infant may have a quite normal blood pressure of 80/45 mm Hg, while that value in an adult is considered low. A teenager may have an acceptable blood pressure of 110/70 mm Hg, but that value would be of concern in a toddler.
The National High Blood Pressure Education Program (NHBEP) recently prepared tables that help a physician determine when your child's blood pressure is higher than other children's blood pressure. The NHBEP prepared a table for boys and a separate one for girls. A range of blood pressure values is given based on how old and how tall your child is. According to the tables, If your child has a blood pressure that is higher than 90 to 95 percent of other boys or girls his/her age and height, then he or she may have high blood pressure.
Again, many factors, including emotions, can affect blood pressure. Readings that are high compared to the values on the table may need to be investigated further by your child's physician.
Why is high blood pressure a concern?
High blood pressure, or hypertension, directly increases the risk of coronary heart disease (heart attack) and stroke (brain attack). With high blood pressure, the arteries may have an increased resistance against the flow of blood, causing the heart to pump harder to circulate the blood.
Heart attack and stroke related to high blood pressure are rare in children and adolescents. Yet, studies of young adults with high blood pressure found that many had high blood pressure as a child. By their 20s, studies show that children and adolescents with high blood pressure will exhibit harmful effects on the heart and blood vessels even with mild hypertension.
What causes high blood pressure?
Blood pressure is classified as primary, or without a definite cause, and secondary, or related to an illness or behavior. Factors that seem to contribute to primary hypertension in adults, and possibly in children, include the following:
- high blood cholesterol levels
- being overweight
Who is at risk for developing high blood pressure?
- Primary hypertension (with an unknown cause) is the most common cause of high blood pressure in adolescents and Many children with high blood pressure also have adult relatives with hypertension, so there may be a hereditary aspect to the disease.
- There is a higher incidence of high blood pressure in African-American children after the age of 12 and into adulthood.
How is high blood pressure diagnosed?
Your child's physician may note an elevated blood pressure reading during a routine office visit. Obtaining calm, resting blood pressures on several different occasions (days, weeks, or months apart) will provide better information about whether the blood pressure elevation is consistent or due to fear or stress.
Your child's physician will obtain a medical history, including information about your child's diet, exercise level, home and school activities, and possible stressors. A physical examination may also be performed.
Diagnostic tests may help determine if your child's high blood pressure is related to an illness, or is essential or primary hypertension, meaning it has no known cause. Diagnostic procedures may include:
- blood tests (including those to evaluate kidney function and cholesterol levels)
- Other tests may be needed to evaluate the health of other organs (such as the heart or kidneys) which may contribute to hypertension.
Treatment for high blood pressure
Specific treatment for high blood pressure will be determined by your child's physician based on:
- your child's age, overall health, and medical history
- extent of the condition
- your child's tolerance for specific medications, procedures, or therapies
- expectations for the course of the condition
- your opinion or preference
If a secondary cause has been found, such as kidney disease, the underlying disease will be treated. If no cause has been determined, the first treatment approach is lifestyle therapy, including the following:
- weight reduction
- increasing physical activity
- healthy diet
These interventions can lower systolic and diastolic blood pressure, improve the strength of the heart, and lower blood cholesterol - all important steps in preventing heart disease as an adult. Medications to control high blood pressure are only needed in about 1 percent of children with the disorder. Consult your child's physician for more information.