Validation of polar verity sense for heart rate monitoring during school-based high-intensity interval training in adolescents.

The polar verity sense (PVS) is a user-friendly heart rate monitoring tool for field-based research compared to Polar H10. However, its validity in the real world (e.g., school settings) among children and adolescents is yet to be determined. Thirty-nine adolescents (12.2 ± 0.4 years, 25 males) participated in a 6-min resistance-based high-intensity interval training (HIIT) session. Heart rate was simultaneously measured by PVS and Polar H10 (criterion measure). Validation metrics included within-participant correlation, mean absolute error, mean absolute percentage error and Bland-Altman plots. Overall, PVS showed very strong within-participant correlation (r = 0.93, p < .001) with Polar H10. The mean absolute and percentage error was 4 b·min-1 and 2.8%, respectively. The correlation between PVS and Polar H10 decreased (r = 0.84, p < .001) for data above the HIIT intensity threshold (≥80% maximal heart rate) but maintained a strong relationship. The validity of PVS remained similar when accounting for sex, body mass index, waist circumference or cardiorespiratory fitness. PVS demonstrated strong agreement with Polar H10 in monitoring heart rate during HIIT in adolescents within a school setting. Therefore, it is valid to replace traditional inconvenient chest strap heart rate monitors with a practical and ergonomic armband PVS, which could largely enhance the feasibility of HIIT fidelity monitoring.