AbstractAims To explore the effects of age and sex in adolescents vs. young or middle-aged adults on pulmonary vascular function and right ventricular-arterial (RV-PA) coupling as assessed by exercise stress echocardiography.Methods and results Forty healthy adolescents aged 12–15 years were compared with 40 young adults aged 17–22 years and 40 middle-aged adults aged 30–50 years. Sex distribution was equal in the three groups. All the subjects underwent an exercise stress echocardiography. A pulmonary vascular distensibility coefficient α was determined from multipoint pulmonary vascular pressure–flow relationships. RV-PA coupling was assessed by the tricuspid annular plane systolic excursion (TAPSE) to systolic pulmonary artery pressure (PASP) ratio, who has been previously validated by invasive study. While cardiac index and mean PAP were not different, adolescents compared to young and middle-aged adults, respectively had higher pulmonary vascular distensibility coefficients α (1.60 ± 0.31%/mmHg vs. 1.39 ± 0.29%/mmHg vs. 1.20 ± 0.35%/mmHg, P < 0.00001). Adolescents and young adults compared to middle-aged adults, respectively had higher TAPSE/PASP ratios at rest (1.24 ± 0.18 mm/mmHg and 1.22 ± 0.17 mm/mmHg vs. 1.07 ± 0.18 mm/mmHg, P < 0.008) and during exercise (0.86 ± 0.24, 0.80 ± 0.15 and 0.72 ± 0.15 mm/mmHg, P < 0.04). The TAPSE/PASP ratio decreased with exercise. There were no sex differences in α or TAPSE/PASP.Conclusion Compared to adults, adolescents present with a sex-independent more distensible pulmonary circulation. Resting and exercise RV-PA coupling is decreased in middle-aged adults.