Rationale: Evidence regarding exercise capacity and physical activity in children born extremely preterm (EP) is limited. Since survivors remain at high risk for developing bronchopulmonary dysplasia (BPD) and long-term pulmonary sequelae, reductions in exercise capacity and activity levels may be present.
Objectives: To compare maximal exercise ventilation characteristics and physical activity levels at 11 years of age in children born EP (<25 completed weeks gestation) with those of full-term controls.
Methods: Participants performed spirometry, body plethysmography and gas transfer testing. A peak exercise test was performed on a cycle ergometer. Physical activity was monitored by accelerometry for seven days.
Main results: Lung function and exercise results were obtained in 38 EP children (71% prior BPD) and 38 controls. Those born EP had significantly lower Z-scores (mean [95% CI] of difference) for FEV1 (-1.74[-2.25;-1.23] and gas transfer (-0.73[-1.31;-0.17], and significantly greater Z-scores for residual volume (0.58[0.10;1.10]) and RV/TLC (0.74[0.29;1.19]). EP birth was associated with a significant reduction in peak oxygen consumption. EP children employed greater breathing frequencies and lower tidal volumes during peak exercise. No differences were observed in physical activity between groups.
Conclusions: The reduction in peak oxygen consumption in children born EP, and alterations in ventilatory adaptations during peak exercise was not explained by differences in physical activity, but probably reflects long-term patho-physiological impact of EP birth.