Correlation between Heart Rate Variability and Pulmonary Function Tests in Healthy Young Adults: A Gender-Specific Analysis

AbstractBackground: The autonomic nervous system (ANS) regulates both cardiac and pulmonary functions. Heart Rate Variability (HRV) is a non-invasive marker of autonomic activity, but its correlation with pulmonary function tests (PFTs) in healthy young adults is not well-established, particularly regarding gender differences.Objective: This study aimed to investigate the correlation between short-term HRV indices and PFT parameters in healthy young adults and to assess gender-based variations in this relationship.Methods: A cross-sectional study was conducted on 80 healthy participants (40 males, 40 females) aged 18-21 years. Short-term HRV (5-minute recording) was analyzed for Low-Frequency (LF), High-Frequency (HF) power, and LF/HF ratio. Spirometry was performed to measure Forced Expiratory Volume in 1 second (FEV1), Forced Vital Capacity (FVC), and FEV1/FVC ratio. Statistical analysis was performed using paired t-tests and Pearson's correlation.Results: Males had significantly higher FEV1 and FVC values than females (p < 0.001), while the FEV1/FVC ratio was comparable. No significant gender differences were found in BMI, blood pressure, heart rate, or any HRV indices (LF, HF, LF/HF). Correlation analysis revealed weak and gender-specific associations. In males, weak negative correlations were found between LF & FVC (r = -0.248) and HF & FVC (r = -0.171). In females, a very weak negative correlation was observed between HF and FVC (r = -0.070). The LF/HF ratio showed a weak positive correlation with FEV1/FVC in males (r = 0.284).Conclusion: While significant gender differences exist in lung volumes, the correlation between resting autonomic tone (as measured by HRV) and pulmonary function is weak in healthy young adults. This suggests that in a healthy, baseline state, pulmonary function is predominantly influenced by anatomical and physical factors rather than acute autonomic modulation. The subtle gender-specific correlation patterns may indicate different autonomic-respiratory interactions warranting further investigation.