Currently WiFi is one of those technologies that is pretty much prevalent across the world, you go to the smallest (inhabited) island in the middle of nowhere and you will get a WiFi signal. Which is why folks have been trying to use it for various tasks such as identifying people or as motion sensors etc.
Building on that researchers at University of California, Santa Cruz have created a system that allows them to measure the heart rate using the signal from a household WiFi device with state-of-the-art accuracy—without the need for a wearable. The system called “Pulse-Fi,” was published in the proceedings of the 2025 IEEE International Conference on Distributed Computing in Smart Systems and the Internet of Things (DCOSS-IoT).
Non-intrusive monitoring of vital signs has become increasingly important in various healthcare settings. In this paper, we present Pulse-Fi, a novel low-cost system that uses Wi-Fi Channel State Information (CSI) and machine learning to accurately monitor heart rate. Pulse-Fi operates using low-cost commodity devices, making it more accessible and cost-effective. It uses a signal processing pipeline to process CSI data fed into a custom low-compute Long Short-Term Memory (LSTM) neural network model. We evaluated Pulse-Fi using two datasets: one that we collected locally using ESP32 devices named ESP-HR-CSI Dataset and another containing recordings of 118 participants using the Raspberry Pi 4B called EHealth, making it the most comprehensive data set of its kind. Our results show that Pulse-Fi can effectively estimate heart rate from CSI signals with comparable or better accuracy than hardware with multiple antenna systems, which can be expensive.
The ability to monitor the health of any person remotely without the cost of a wearable or extra sensors is pretty groundbreaking. I can see it in use at hospitals, elderly care and nursing homes etc. However, as with all technologies there is a downside as well. Once we have the ability to monitor the pulse of anyone remotely, I can see the various security and government agencies around the world falling over each other to get it implemented as widely as possible. Imagine having this at an airport where you can monitor for abnormal heartbeat or increase in pulse rate to watch out for a suicide bomber (never mind the poor nervous flyer who got tackled out of nowhere or the person nervous about their first date). Offices with sensitive data or intelligence agencies will end up using it as a non-stop lie/threat detector.
But that is still in the future as the technology is still in an early stage and it is not clear how accurate it will be when used in a crowded location.
Source: ucsc.edu: WiFi signals can measure heart rate—no wearables needed
– Suramya