Patterns of physical activity defined by continuous heart rate monitoring among children from Liège

Health benefits of a physically active lifestyle are well documented. We therefore investigated the physical activity patterns of 200 children from Liège. They were monitored continuously using a 24-hour Holter monitoring system during normal weekdays and the percentage of heart rate reserve (%HRR) was used to measure the amounts of physical activity at different intensities. Preschool children attained 184.3+/-54.2, 40.7+/-16.1, 15.8+/-6.9 and 6.0+/-7.2 minutes/day (mean+/-SD) between 20% to 40%, 40% to 50%, 50% to 60%, and greater than 60% of HRR, respectively. At the same %HRR intensities, schoolchildren attained 165.6+/-74.6, 32.1+/-12.1, 15.8+/-6.7 and 7.0+/-5.9 minutes/day, and teenagers attained 159.2+/-68.3, 32.1+/-23.5, 13.1+/-6.0 and 6.1+/-6.3 minutes/day. Age was a significant predictor of the intercept and slope of the time spent in physical activity and %HRR relationship. In Liège the average youth accumulates +/-30 to 40 minutes/day of moderate-intensity physical activity and +/-20 minutes/day of high-intensity physical activity. Those children meet the classical revised guidelines for physical activity but do not compare favourably with children from elsewhere. On the other hand, they get more than 2 1/2 to 3 hours/day of low-intensity physical activity. Our findings suggest that children from Liège are not engaged in sedentary behaviour but do not experience the ideal amount and type of physical activity classically believed to benefit the cardiopulmonary system. Public health strategies should be adapted to our findings.