The Challenge of Measuring Exercise: Advancing Metrological Barriers in Wearable Sensing (Preprint)

UNSTRUCTURED Regular physical activity offers extensive health benefits, yet current consumer wearables struggle to accurately quantify these effects at an individualized level. Sensor performance often falls short due to susceptibility to interferences, non-standardized validation, and reliance on indirect estimations. Further, sensors often cannot capture or account for inequalities between measurement types, populations, physiological, and anatomical characteristics, nor the influence of different exercise modalities on an personalized scale. There is a drive for developers to refine the impact of how we measure the benefits of exercise, improving the usefulness of data through advanced optical modeling and spectroscopic applications. This review critically examines the shortcomings of prevailing non-invasive measurements and techniques used in common, commercially available fitness trackers, and describes why it is difficult to quantify the effects of exercise as an individualized, quality-based metric. Next, we discuss newer sensing applications that attempt to curtail known limitations, some of which may unveil novel biometric insights through differentiated approaches, bridging gaps not only in technological advancement but physiological metrology. In conclusion, we believe that new sensing techniques should explore solutions beyond population-based statistics and aim to provide an individualized understanding of a person’s response to exercise, while also reducing disparities in personalized health monitoring. The results could lead to a more effective understanding of exercise efficacy and its impact on performance management and clinical outcomes.