RT Journal Article SR Electronic T1 Alleviating mechanical constraints to ventilation with heliox improves exercise endurance in adult survivors of very preterm birth JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 302 OP 304 DO 10.1136/thoraxjnl-2018-212346 VO 74 IS 3 A1 Joseph W Duke A1 Amy M Zidron A1 Igor M Gladstone A1 Andrew T Lovering YR 2019 UL http://thorax.bmj.com/content/74/3/302.abstract AB Adult survivors of very preterm birth (PRET) have significantly lower aerobic exercise capacities than their counterparts born at term (CONT), but the underlying cause is unknown. To test whether expiratory flow limitation (EFL) during exercise negatively affects exercise endurance in PRET, we had PRET and CONT exercise to exhaustion breathing air and again breathing heliox. In PRET, EFL decreased and time-to-exhaustion increased significantly while breathing heliox. Heliox had a minimal effect on EFL and had no effect on time-to-exhaustion in CONT. We conclude that aerobic exercise endurance in PRET is limited, in part, by mechanical ventilatory constraints, specifically EFL.