RESUMEN
AIM: This study investigated the accuracy and reliability of short-term resting heart rate variability (HRV) assessment by fingertip photoplethysmography (PPG) and using a cardiofrequencimeter (Polar RS800cx) in obese adolescents. Obesity in adolescents may be related to autonomic dysfunction due to insulin resistance and/or increased central fat. This fact may affect the accuracy and reliability of the evaluation of autonomic activity at rest. METHODS: Fourteen adolescents (15±2 years) classified as obese and exhibiting insulin resistance underwent the following procedures: (a) anthropometric measurements, and (b) two 25-min HRV recordings in a supine position conducted simultaneously using ECG, PPG, and Polar RS800cx. RESULTS: The results showed significant correlations between HRV markers obtained using Polar RS800cx and PPG and those obtained from ECG, with coefficients of determination (R) and intraclass correlation coefficients ranging from 0.60 to 0.98 (P-value ranging from 0.03 to 0.05) and 0.70 to 0.99 (P-value ranging from 0.01 to 0.05), respectively. The technical error of measurement and intraclass correlation coefficients for test-retest reliability ranged from 8.9 to 45.8% and 0.38 to 0.68 for ECG, 8.0 to 30.5% and 0.29 to 0.61 for Polar RS800cx, and 7.2 to 54.6% and 0.45 to 0.64 for PPG, respectively. CONCLUSION: HRV indices calculated by Polar RS800cx and PPG appear to be as accurate and reproducible as data from ECG when evaluating the autonomic control of heart rate at rest in obese adolescents.