Optimal level of physical activity in children with chronic lung diseases

Abstract

To determine the optimal level of physical activity and its relationship with disease severity in children with chronic lung diseases (CLD). Pulmonary function and exercise tests were compared between 18 CLD children (aged 13.5 +/- 2.4 years, 33% male) and 18 healthy controls without any history of lung diseases (age and sex matched). CLD children had lower forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV)(1), forced expiratory flow rate between 25% and 75% of vital capacity (FEF)(25-75%) and total lung capacity (TLC) and higher residual volume (RV)/TLC ratio than controls (77.3 +/- 22.6 vs. 97.9 +/- 12.5%pred; p = 0.002, 74.3 +/- 17.6 vs. 104.0 +/- 12.6%pred; p < 0.001, 49.9 +/- 23.1 vs. 75.6 +/- 18.6%pred; p < 0.001, 82.8 +/- 18.6 vs. 95.6 +/- 9.8%pred; p = 0.04, 30.8 +/- 10.2 vs. 24.4 +/- 5.9%; p = 0.04, respectively). Oxygen consumption at anaerobic threshold (AT) and optimal level of physical activity (metabolic equivalents [METs] at AT) were not different between the two groups and between mild and moderate to severe CLD. However, when the exercise was continued beyond the AT, CLD children demonstrated poorer exercise performance than normal controls. Children with CLD demonstrated the same level of optimal physical activity as normal children despite their lower lung function. The optimal level of physical activity was not related to disease severity. The exercise test and exercise should not be performed beyond the AT by the CLD children. Proper exercise test should be done to determine their optimal exercise activity.