Validation of the maximal cardiopulmonary exercise test in adolescents with major depressive disorder and comparison of cardiorespiratory fitness with sex- and age-related control values.

Endurance training has been shown to be effective in treating adolescents with major depressive disorder (MDD). To integrate endurance training into the therapeutic setting and the adolescents' daily lives, the current performance status of the adolescents should be accurately assessed. This study aims to examine adolescents with MDD concerning exhaustion criteria during a cardiopulmonary exercise test (CPET), as well as to compare the values obtained thereon with sex- and age-related control values. The study included a retrospective examination of exhaustion criteria ((i) oxygen consumption (V̇O) plateau, (ii) peak respiratory exchange ratio (RER) > 1.0, (iii) peak heart rate (HR) ≥ 95% of the age-predicted maximal HR, and (iv) peak blood lactate concentration (BLC) > 8.0 mmol⋅L) during a graded CPET on a cycle ergometer in adolescents with MDD (n = 57). Subsequently, maximal V̇O, peak minute ventilation, V̇O at the first ventilatory threshold, and peak work rate of participants who met at least two of four criteria were compared with published control values using an independent-sample t-test. Thirty-three percent of the total population achieved a V̇O plateau and 75% a RER > 1.0. The HR and BLC criteria were met by 19% and 22%, respectively. T-test results revealed significant differences between adolescents with MDD and control values for all outcomes. Adolescents with MDD achieved between 56% and 83% of control values.   Conclusions: The study shows that compared with control values, fewer adolescents with MDD achieve the exhaustion criteria on a CPET and adolescents with MDD have significantly lower cardiorespiratory fitness.   Clinical trial registration: No. U1111-1145-1854. What is Known: • It is already known that endurance training has a positive effect on depressive symptoms. What is New: • A relevant proportion of adolescents with major depressive disorder do not achieve their V̇O2max during a graded cardiopulmonary exercise test. • Adolescents with major depressive disorder have significantly lower cardiorespiratory fitness compared to sex- and age-related control values.