Association Between Heart Rate Variability And Peak Expiratory Flow Rate In Adolescents With Cardiovascular Risk

Background: Heart rate variability (HRV) is a non-invasive marker of autonomic nervous system (ANS) function, while peak expiratory flow rate (PEFR) assesses airway patency. This study aimed to examine the association between HRV parameters and PEFR in adolescents with cardiovascular (CV) risk factors such as obesity and a family history of hypertension (HT) or diabetes mellitus (DM).Methods: A cross-sectional study was conducted among 29 adolescents (14 girls, 15 boys) aged 14–15 years from local schools. Participants were obese and/or had a family history of HT or DM. Anthropometric data, blood pressure (BP), HRV (time and frequency domain indices), and PEFR were recorded. HRV was derived from 15-minute ECG recordings. PEFR was measured using a calibrated peak flow meter. Statistical analysis involved Pearson correlation, with p < 0.05 considered significant.Results: Boys had significantly higher PEFR (419.33 ± 52.57 L/min) than girls (379.28 ± 35.40 L/min). HRV parameters showed no statistically significant gender differences, although average RR intervals and parasympathetic indices (RMSSD, pRR50) were slightly higher in boys. In boys, PEFR positively correlated with SDRR, LFnu, and LF/HF, but negatively with RMSSD and HFnu. In girls, PEFR showed negative correlations with LFnu and LF/HF, with RMSSD and HFnu showing weak positive associations. Conclusion: HRV parameters exhibit gender-specific associations with pulmonary function in adolescents at CV risk. These findings suggest differential autonomic regulation of airway dynamics, with potential implications for early preventive strategies.