CIRCADIAN-RHYTHM OF BLOOD-PRESSURE IN HEALTHY SCHOOLCHILDREN (AGED 6-10 YEARS)

Ambulatory blood pressure monitoring was performed in 240 healthy children (135 boys, 105 girls) aged 6 - 10 years (mean age = 8.3 years). We used the Spacelabs 90207 monitor. The mean day-night difference of systolic blood pressure (SBP) was 11.8 +/- 4.4 mmHg in boys and 10.6 +/- 6.8 mmHg in girls. The nocturnal fall of diastolic blood pressure (DBP) was 13.4 +/- 5.5 mmHg in boys and 13.2 +/- 6.5 mmHg in girls. No significant change of nocturnal BP fall was found whith increase in age. When related to the daytime BP level there is a very distinct nocturnal fall of DBP (nocturnal fall of BP as percent of daytime BP level: 10.7% in boys and 9.7% in girls for SBP, 19.1% in boys and 18.9% in girls for DBP). With regard to these data there is a marked circadian rhythm of BP in young children. The nocturnal fall of BP is more distinct in DBP. A nocturnal BP fall of less than 5 mmHg in SBP or of less than 7 mmHg in DBP should be regarded as remarkable.