Blood pressure responses in Japanese and Swedish children in the supine and standing position.

We investigated the cardiovascular responses to active standing in Swedish and Japanese pre-pubertal children using non-invasive continuous beat-to-beat finger blood pressure (BP) monitoring. Seventy-eight Swedish (7-12 years) and 53 Japanese children (6-12 years) were examined. There were no significant differences in body weight or height between the two groups (total group). Finger blood pressure and heart rate were continuously recorded in the supine position and during standing. Supine BP was significantly higher in Swedish compared to Japanese children (115/65 vs 98/50 mmHg, P < 0.001), and Swedish children showed a significantly larger initial BP drop upon rising (-28/15 vs - 14/ -10 mmHg, P < 0.05) and a larger increment of heart rate (39 +/- 10 vs 29 +/- 8 beats. min-1, P < 0.05). There were, however, no differences in the blood pressure and heart rate changes in the following steady state period (2-3 min) between the two groups. These results suggest that Swedish pre-pubertal children have a higher basal blood pressure and enhanced cardiovascular autonomic responses, such as pronounced baroreflex receptor sensitivity and vasoconstrictor mechanisms. These differences in the two cohorts were not related to body dimensions or degree of maturation, indicating that autonomic functions in the cardiovascular system largely depend on genetic factors and environmental variables.