Watching My Heart Beat

At Wellysis, where I work, one of our products is an FDA-cleared single-lead ECG device. So I thought, why not use it to animate my own heartbeat? You’ve seen those pulsing heart animations that just loop on a timer. This is that kind of thing, but every beat comes from a real recording, so it’s a lot more precise. I wore it for a whole day, logged what I was doing in the app’s diary as I went, and then used the diary to cut out one-minute samples from four different moments. The animation plays along with those.

Click Start to play all four. Each row is one 60-second recording, and the heart next to it beats in time with that trace. Peacefully sleeping, my heart was at ~59 BPM, fully caffeinated and technically working at ~75 BPM, a 50 m run to make the zebra crossing at ~140 BPM, and playing Dota 2 on the SEA server at ~127 BPM.

Yes, a game of DOTA 2 in SEA server gets my heart to ~127 BPM, only ~13 BPM less than actually sprinting. If you’ve ever played DOTA 2 on SEA, you already know why.

The heart is timed by a small QRS detector that runs in your browser. It finds the R peaks in the trace and schedules every contraction off them, so a faster heart rate makes the animation pump faster too.

To be clear, this is a toy and not a clinical analysis. If you actually want to know how your heart is doing, that’s the job of the real analysis and a cardiologist. A single ECG lead also can’t tell you valve timing or blood flow, so those parts of the animation are an educated guess built on top of the beat timing.