Techniques for determining blood pressure based on a relative timing of pulses

Abstract

Methods, systems, and devices for synchronizing multiple devices for determining physiological metrics are described. A method may include flashing light-emitting diodes (LEDs) of a wearable device, and capturing images of the flashing LEDs using an imaging device. A synchronization procedure may be performed to identify a delay between internal clocks at the wearable device and the imaging device based on capturing the images. Subsequently, the wearable device and the imaging device may collect physiological data at different physiological locations on the user's body, where the physiological data includes separate pulse observation times of a heartbeat of the user at the different physiological locations. Subsequently a pulse transmit time (PTT) associated with the heartbeat may be determined based on the delay and a comparison between the pulse observation times, and a blood pressure metric for the user is determined based on the PTT.