Physical Performance and Heart Rate Variability According to Different Self-Reported Physical Activity Levels in Youth with Cerebral Palsy: An Exploratory Cross-Sectional Study

Abstract Heart rate variability (HRV) is a non-invasive indicator of autonomic nervous system function and generally improves with regular physical activity. Individuals with cerebral palsy (CP) often present impaired cardiac autonomic regulation; however, differences in HRV across physical activity levels in this population remain unclear. This study compared physical performance and HRV across different levels of physical activity in youth with CP. Eighteen participants (15 males and 3 females; 15.72 ± 0.96 years), all classified as level I according to the Gross Motor Function Classification System (GMFCS), were grouped into low, moderate, and high self-reported physical activity levels using the Physical Activity Questionnaire for Adolescents (PAQ-A). Physical performance was assessed through the shuttle run test and the muscle power sprint test, while HRV was measured at rest using heart rate monitors. Exploratory between-group differences were observed between the low- and high-self-reported physical activity groups in cardiorespiratory endurance ( p = 0.009) and sprint performance ( p = 0.045). The high PAQ-A-based self-reported physical activity group also presented a lower low-to high-frequency (LF/HF) ratio compared with the low activity group ( p = 0.049), whereas no differences were found for SDNN ( p = 0.767). Higher PAQ-A scores showed non-significant trends toward associations with lower BMI, greater shuttle run distance, and faster sprint times, while higher standard deviation of normal R-R intervals (SDNN) values tended to be associated with lower BMI. These findings should be interpreted cautiously given that none of the correlations remained statistically significant after correction for multiple comparisons, as well as the exploratory nature of the analyses and the small sample size. Overall, higher self-reported physical activity levels were associated with better physical performance and a potentially more favorable autonomic profile in youth with CP. Given the cross-sectional and preliminary nature of the study, future research using larger samples, objective activity measures, and longitudinal designs is warranted.