Cardiorespiratory Fitness Assessed by Direct VO₂peak Measurement in Adolescent and Young Adult Males With Developmental Disorders

Introduction Individuals with developmental disorders (DD) often exhibit reduced levels of daily physical activity, contributing to diminished cardiorespiratory fitness. While field-based tests such as the 20-meter shuttle run and six-minute walk test are commonly used for indirect assessment, few studies have employed direct measurement of peak oxygen uptake (VO2peak), the gold standard for evaluating aerobic capacity. This study aimed to evaluate VO2peak using a maximal exercise test in adolescent and young adult males with developmental disorders. Methods A cross-sectional study was conducted with 41 male participants aged 15-20 years with diagnosed developmental disorders. After excluding individuals with BMI >30, 37 participants completed a ramp protocol maximal exercise test on a cycle ergometer. VO2peak was measured using breath-by-breath gas analysis. Values were compared to established normative data for healthy Japanese males of similar age. Results The mean absolute VO2peak was 2209.9 ± 458 mL/min, and the weight-adjusted VO2peak was 38.1 ± 6.8 mL/min/kg. Only 6 out of 37 participants fell within the normative range (95% CI: 44.2-60.2 mL/min/kg), indicating significantly reduced cardiorespiratory fitness in this population. This study is among the first to report directly measured VO2peak using a ramp protocol in individuals with developmental disorders. Conclusion Adolescent and young adult males with developmental disorders demonstrated substantially lower VO2peak values compared to their typically developing peers. These findings highlight the need for targeted physical activity interventions and provide reference data for future research in this under-investigated population.