When blood flows through our bodies, it experiences pressure in two ways: from the heart that pumps it and from the walls of the arteries resisting it. This is called blood pressure, and it's affected by the body's state of rest, temperature, posture, and emotional state, as well as diet and medication. High blood pressure causes extra strain on the heart and arteries and increase the risk of heart disease and stroke, while low blood pressure can cause dizziness. Optimal blood pressure falls between these extremes, and is calculated in children based on gender, age and height.
Blood pressure is measured using a stethoscope and a sphygmomanometer, which contains a rubber cuff to wrap around the upper arm and a pump to inflate it with air. When inflated, pressure stops the blood flow for a moment. Then, as air is released from the cuff, the blood flow starts up again. Using a stethoscope, the doctor can hear two sounds: the highest pressure, at the heartbeat's peak, is called the systolic pressure; the lowest pressure, between heartbeats, is called the diastolic pressure.
Blood pressure is given as two numbers, which is the systolic pressure over the diastolic pressure. For example, a blood pressure reading of 120/80 means the systolic pressure is 120 and the diastolic pressure is 80.
In children, height has a significant effect; taller kids have higher blood pressure. So a normal blood pressure range for children accounts for age, height and gender.
3 to 5 Years Old
The American Heart Association and the American Academy of Pediatrics recommend that children have their blood pressure checked regularly, beginning at three years.
The upper limit for normal systolic pressure in kids aged three to five will range from 104 to 116, depending on height and gender. The upper limit for diastolic pressure will range from 63 to 74.
For a three-year-old boy, normal systolic pressure is 104 at the 5th percentile for height, and 113 for the 95th percentile. Diastolic pressure ranges from 63 to 67. At four, the range is 106 to 115 for systolic pressure, and 66 to 71 for diastolic pressure. At five, it's 108 to 116 for systolic and 69 to 74 for diastolic.
For a three-year-old girl, systolic pressure ranges from 104 at the 5th percentile for height to 110 at the 95th percentile, while diastolic pressure ranges from 65 to 68. At four years old, the systolic range is 105 to 111 and the diastolic range is 67 to 71. At five, the systolic range is 107 to 113 and the diastolic range is 69 to 73.
6 to 9 Years Old
Children aged six to nine range from 108 to 121 for the upper limit of normal systolic pressure, depending on height and gender, and 71 to 81 for diastolic pressure.
For boys, at six years old the range for systolic pressure is 109 at the 5th percentile for height, to 117 at the 95th percentile, and the diastolic range is 72 to 76. At seven years old, systolic pressure ranges from 110 to 119 and diastolic pressure from 74 to 78. At eight, the systolic range is 111 to 120 and diastolic is 75 to 80. At nine, systolic pressure ranges from 113 to 121 and diastolic from 76-81.
For a six-year-old girl, systolic pressure ranges from 108 at the 5th percentile for height to 114 at the 95th percentile, and diastolic ranges from 71 to 75. At seven years old, her systolic pressure will be 110 to 116, and her diastolic pressure 73 to 76. At eight, the systolic range is 112 to 118, and the diastolic range is 74 to 78. At nine, the systolic pressure ranges from 114 to 120, while the diastolic pressure ranges from 75 to 79.
10 to 12 Years Old
Kids that are 10 to 12 years old have an upper limit of normal systolic pressure that ranges from 114 to 127, depending on height and gender, and a diastolic pressure that ranges from 77 to 83.
A 10-year-old boy has a systolic pressure range of 114 to 123 and a diastolic range from 77 to 82. At 11, he has a systolic range of 116 to 125 and a diastolic range of 78 to 83. At 12, his systolic pressure ranges from 119 to 127 while his diastolic pressure ranges from 79 to 83.
For girls, a 10-year-old has a normal systolic pressure between 116 and 122, and a normal diastolic pressure between 77 and 80. At 11, her systolic range is 118 to 124 and her diastolic range 78 to 83. At 12, her systolic pressure ranges from 120 to 126, while her diastolic pressure ranges from 79 to 82.