Technological innovations are driving the expansion of wearable devices. These are non-invasive on-body sensors that continuously and wirelessly measure clinically relevant parameters, which can be integrated into healthcare ecosystems and distributed as regulated devices. In this work, Xu et al. review the current and emerging wearables, translational gaps, challenges, and opportunities associated with their implementation. While existing wearable devices can track some biophysical and biochemical parameters, they are constrained by placement, with most devices being worn on the wrist, fingers, or skin. However, new advancements are expanding placement options and sensor capabilities. Innovations include wearable necklaces to monitor cardiac outputs, integration with clothing to assess sweat biochemistry, and contact lenses for eye disease monitoring. Xu et al. identify three areas of opportunities for wearable devices: early life applications, including pregnancy monitoring and neonatal follow-up; end-of-life care, with continuous monitoring of vital signs and new measurements; and infectious disease surveillance, leveraging remote monitoring and population-level data integration. Despite their potential, wearable development and implementation face challenges beyond technological constraints, such as the clinical validation of patient outcomes, the need for regulatory bodies to keep up with technological innovations, and concerns over privacy and data protection. Nevertheless, medical-grade wearables hold great promise for improving diagnostics, monitoring, patient care, and disease prevention.