Blood pressure, measured in millimeters of mercury (mmHg), identifies how quickly blood moves through the body's vessels. Health professionals measure blood pressure by listening for the sound of moving blood when a vessel is closed and opened by the blood pressure cuff. Although normal blood pressure in adults averages 120/80 mmHg, blood pressure in children may start quite low and increase with greater age and size.
Normal Blood Pressure Patterns
Normal blood pressure measurements in children are scaled differently for boys and girls and according to age. An additional component of the scale for blood pressure is height percentile. Unlike adult measurements, pediatric blood pressure measurements are separated into percentiles. When blood pressure numbers and height percentile are charted against a child's age, the blood pressure percentile is identified to determine health.
Upper Normal Blood Pressure Limit
Normal blood pressure in children is considered any blood pressure lower than the 95th percentile, and the 90th to 95th percentiles are considered pre-hypertension stages. For example, a 3-year-old boy in the 50th percentile for height who had a blood pressure measurement of 105/61 mmHg would be in the 90th blood pressure percentile and could be diagnosed with pre-hypertension.
Normal Blood Pressure Goals
Because blood pressure fluctuates so much with children as they grow and age, diagnosis or monitoring of blood pressure problems should include at least two separate measurements at two different office visits. For children who already have high blood pressure concerns, a normal blood pressure goal is the lowest of either 130/80 mmHg or the 50th percentile (i.e., a normal charted blood pressure) on a blood pressure chart.
Normal Blood Pressure Ranges
Although normal ranges of pressure are broad across the 50th to 90th percentiles, some trends and standards are defined. A typical example of normal blood pressure in a 1-year-old child would be 70/40 mmHg to 90/60 mmHg, and the cut-off high value would be approximately 103/55 mmHg. In healthy children, both upper and lower blood pressure numbers increase proportionally with age and growth through age 17 years. An example of normal blood pressure in a 17-year-old girl is 128/82 mmHg; after this age, adult measurements and guidelines for blood pressure are used.
