Abstract Body: Introduction: Wearable technology paired with mobile device applications can provide a convenient, low-barrier method to investigate individual fitness and evaluate cardiovascular (CV) health in a precise and equitable manner. In this study, we aimed to assess the feasibility of the University of Minnesota 3-Minute Heart Health app, analyzing technical function and usability feedback.
Methods: This study was conducted at the Minnesota State Fair, enrolling healthy, asymptomatic adults. Participants were fitted with a Bluetooth continuous heart rate monitor chest band connected to the 3-Minute Heart Health app. They then performed 2 minutes of vigorous exercise followed by 1 minute of recovery (Figure). Subsequently, they completed a survey including demographic questions and the System Usability Scale (SUS). The SUS is a ten-item survey assessing subjective usability. It is scored using a Likert scale from 0 to 100, with values higher than the industry mean SUS score of 68 serving as a good indicator of user satisfaction.
Results: Of the 263 individuals who enrolled, 201 individuals were able to achieve a heart rate necessary to assess CV fitness, a completion rate of over 75%. Twenty-one technical failures were documented, involving an inability to detect heart rate related to issues with Bluetooth connection, band fit, or another unknown problem. A total of 41 individuals (15.6%) were unable to reach an adequate exercise heart rate necessary for the app to provide a heart fitness grade. Of the 201 individuals who completed exercise testing, age ranged from 18 to 90 years. A total of 230 participants completed the SUS survey. Scores indicated that the app was well-accepted; mean SUS score for all survey participants was 75.2. Scores were high across age and education subgroups, including among individuals over 65 years of age (SUS score of 74.1). Participants provided generally positive written feedback after using the app, finding it to be user-friendly. Suggestions for areas of improvement included adding more options for heart rate monitoring, improving the fit of the chest band, and optimizing Bluetooth connectivity.
Conclusions: The participant mean SUS score of 75.2 is well above the accepted benchmark of 68, indicating satisfaction with app usability. Going forward, this app may be an accessible screening tool for asymptomatic individuals to evaluate CV fitness without needing to pursue costly, time-intensive procedures and specialty care.