Noninvasive, and continuous physiological sensing enabled by novel wearable sensors is generating unprecedented diagnostic insights in many medical practices. However, the limited battery capacity of these wearable sensors poses a critical challenge in extending device lifetime in order to prevent omission of informative events. In this work, we exploit the inherent sparsity of physiological signals to intelligently enable selective transmission of these signals and thereby improve the energy efficiency of wearable sensors. We propose STINT, a selective transmission framework that generates a sparse representation of the raw signal based on domainspecific knowledge, and which can be integrated into a wide range of resource-constrained embedded sensing IoT platforms. STINT employs a neural network (NN) for selective transmission: the NN identifies, and transmits only the informative parts of the raw signal, thereby achieving low power operation. We validate STINT and establish its efficacy in the domain of IoT for energy-efficient physiological monitoring, by testing our framework on EcoBP-a novel miniaturized, and wireless continuous blood pressure sensor. Early experimental results on the EcoBP device demonstrate that the STINT-enabled EcoBP sensor outperforms the native platform by 14% of sensor energy consumption, with room for additional energy savings via complementary bluetooth and wireless optimizations.