Cardiopulmonary response to exercise in adults born very preterm

This study aims to compare cardiopulmonary response to aerobic exercise between young adults born very preterm, including a subgroup with bronchopulmonary dysplasia (BPD), and term controls.

71 adults (aged 18-29 years) born <30 weeks gestational age (24 with BPD) and 73 term controls were recruited. Assessment included cardiopulmonary exercise testing with impedance cardiography. We compared group differences in peak oxygen uptake (V'_O2 ) and in ventilatory and cardiovascular responses to exercise using linear regression analyses.

Preterm participants had reduced peak V'_O2 versus controls (mean difference (MD) -2.7 (95% CI -5.3- -0.1) mL per kg lean body mass per min). Those with BPD achieved lower peak work rate compared with term controls (MD -21 (95% CI -38- -5) W). There was no difference across groups in breathing reserve, ventilatory efficiency, peak heart rate and cardiac output. The V'_O2 to work rate relationship (ΔV'_O2 /ΔWR) was reduced in preterm versus term. Peak systolic blood pressure and circulatory power (systolic blood pressure×V'_O2 ) were also lower in BPD versus term controls. In the preterm group, longer neonatal intensive care unit stay and lower peak cardiac output were associated with lower peak V'_O2 .

Results suggest limitations with peripheral oxygen uptake in the muscles with reduced ΔV'_O2 /ΔWR and peak circulatory power, but normal cardiac output. Investigations into skeletal muscle perfusion and oxygen use during exercise are warranted to better understand mechanisms of exercise limitation.