I recently got a new Fitbit, excited about all the fancy health metrics it could track. Steps, sleep, heart rate – the usual suspects. But one metric caught my eye: HRV, or Heart Rate Variability. I'd heard it mentioned in passing but never really paid much attention to it. Curiosity piqued, I checked my score... and was shocked. It was alarmingly low, more in line with someone in their 70s or 80s, not a relatively healthy individual in their early 40s.

This sent me down a bit of a rabbit hole of research. What exactly was HRV? What did it measure, and more importantly, what did my dismal score mean for my health? The more I learned, the more fascinated I became.