Photoplethysmography (PPG) is an optical technique that monitors blood oxygen saturation levels, typically with the use of pulse oximeters. Conventional pulse oximetry estimates the ratio of light absorbed at two wavelengths. Attempts have been made to improve the precision of these measurements by using polarized light, with the tradeoff of requiring multiple sequential measurements. We demonstrate a novel PPG technique that uses radially polarized light generated by a light-emitting diode (LED) to obtain single-shot, blood oxygen-saturation measurements using a single wavelength at a rate of 50 fps. Our work, to the best of our knowledge, presents both a novel use of a vector beam and a first demonstration of vector-beam generation using LEDs.