Ari Daniel | MIT Spectrum
May 2022

Consider A 75-Year-Old We’ll Call Gordon. One day in late February 2020, he had a myocardial infarction—a heart attack—and was rushed to the hospital. Fortunately, Gordon recovered. But he wasn’t able to get back to his previous level of mobility.

What if Gordon had had some warning of what was to come?

It turns out that in the six days preceding his heart attack, Gordon’s walking was gradually slowing and his breathing rate was increasing. The changes were so imperceptible that no one noticed, not even Gordon. But a small device sitting in his bedroom did. Part of a purely observational study at the time, the machine, the size of a router, was continuously emitting wireless signals (about a thousand times weaker than your WiFi).

Those signals, ricocheting off the walls and floors of Gordon’s apartment, also bounced off him. The tiniest of Gordon’s bodily signals—the pulsing of his veins, the inhale-exhale movements of his chest, the shuffling of his feet—affected these waves, enabling changes to be detected. Think of it as low-power radar.

Complete article from MIT Spectrum.