Development, validation and usability evaluation of mobile application to monitor real-time exercise heart rate zone / Muhammad Iskandar Asraff

Conventional heart rate (HR) monitor device and mobile application have been developed with numerical digital displays, and such display is not practical under most exercising condition. This work describes the development of smartphone application called Chromozone designed to monitor exercise HR in real-time using the color-coding system. Chromozone development goals include to: (1) enables real-time communication of HR signal from Bluetooth-enabled HR transmitter to Chromozone application, (2) determine individual HR zone based on maximum HR, age, gender, and selected exercise zone, and (3) to display accurate color-coded which correspond to individual optimal HR zone range in real-time, and this development objective was successfully met. Validation and usability assessment of the developed application were performed in conventional HR monitor users. Chromozone was compared against clinically accepted, laboratory-grade electrocardiogram, and was found to generate excellent criterion-concurrent validity (r = 0.994, p < 0.001) in Spearman rho correlation-coefficient test for absolute agreement, and acceptable bias of 1.96 bpm and narrow limits of agreement (3.07 to -3.51) in Bland Altman test for relative agreement. Similarly, relative (intraclass correlation coefficient test: 0.998, p < 0.001) and absolute (within-subject coefficient of variation: 1.95 ± 1.4 %) reliability test of HR dataset from repeated exercise trials using Chromozone application shows an excellent consistency. Additionally, this study also showed that usability level of Chromozone application is within the satisfactory level, although it is necessary to consider several critical feedbacks from the participants for future version update. The outcome of this work provides a strong support for Chromozone application as a valid, reliable, and effective exercise HR monitoring tool. The application could potentially help athlete, active individual as well as the clinical population to monitor and regulate their exercise training regime in a more effective manner.