Heart rate (HR) and blood oxygen saturation (SpO2) are quickly moving from the “desirable” to the “expected” phase in the list of features available in health and fitness wearables. A consequence of this transition, however, has been a reduction in the quality of readings caused by some sensor manufacturers making questionable claims about the accuracy of their products in the rush to meet the market demand for these features. While the accuracy of readings may not be critical in everyday wearables, the quality and integrity of measurements must be unquestionable in clinical-grade wearables. A key challenge for designers is how to make high quality HR and SpO2 measurements in a way that doesn’t place a heavy drain on the battery of the device. In this design solution, we show why the conventional approach to optical readings wastes power before presenting a sensor IC that uses a novel architecture to substantially reduce power consumption while making clinical-grade measurements.