Blood pressure in schoolchildren measured under standardized conditions

The blood pressures of 6346 children who were between the ages of seven and 17 years were measured under standardized conditions. Blood pressures were similar in prepubertal boys and girls. After puberty, the systolic blood pressures of the girls remained unchanged whereas those of the boys continued to rise. The difference between the fourth and fifth Korotkoff sounds was 2 mm at both the 50th and 95th percentiles. The systolic blood pressure was observed to fall over a 10-min period by 4-9 mmHg at the 50th percentile and 9-15 mmHg at the 95th percentile. Over the same period of time, the diastolic blood pressure was seen to fall by 2-3 mmHg and 3-6 mmHg at the 50th and 95th percentiles, respectively. There was no further fall in blood pressure after 10 min. The conditions and timing of measurement are important in blood-pressure evaluation and may explain the differences in blood pressure that have been reported for different populations.