Abstract

The purpose of the study was to examine the physical activity patterns of 67 (34 male, 33 female) second-, fifth-, and seventh-grade (9-13 yr) children. Minute-by-minute heart rates (HR) were obtained from a continuous ECG recording device worn for a 10-hr period (9 a.m.-7 p.m.) during a week day. The mean HR for both males and females in all three grades were surprisingly low (90-110 bts/min) throughout the monitoring period. After grouping the HRs into four predefined intervals, (120-139, 140-159, 160-179, more than 180 bts/min), it was evident that across grade and sex the mean time (n=600 min) spent at higher HR between 160-179 bts/min (7.2 min) and more than 180 bts/min (4.9 min) was short. Examination of the duration and frequency above the 4 predefined HR intervals for all groups showed the mean number of times the HR exceeded 160 (5.6) and 180 (2.9) bts/min was few. In addition, the mean duration above each of these HR levels was 1.5 min, indicating the higher intensity activity was discontinuous. Verf.-Referat