Short-range shape
Recent HRV readings stay close to the surface, useful for spotting the shape of a day as it develops.
Apple Watch + HealthKit HRV
Your HRV. Raw. Beautiful. On your wrist.
HRVSpark turns your HealthKit heart-rate variability samples into calm, glanceable watch-face sparklines. No readiness score. No stress label. No verdict between you and the signal.
Built for glanceable raw HRV
A window, not a verdict.
Heart Rate Variability can be a useful window into recovery, strain, and autonomic state. But the moment a product turns that signal into a score, color, or warning, it starts shaping how you feel before you have even looked at the data.
HRVSpark takes the quieter path. It puts the raw HRV shape where you can see it repeatedly: on the Apple Watch face you already check all day.
You bring the context. The app brings the window.
The instrument
HRVSpark is deliberately calm: high contrast where it helps, soft glow where it belongs, and no color-coded judgement attached to the value. The watch face becomes a small instrument panel instead of a daily report card.
HealthKit in view
Recent HRV readings stay close to the surface, useful for spotting the shape of a day as it develops.
A full-day window helps separate single readings from the broader rhythm of sleep, work, movement, recovery, and intervention.
The seven-day view makes repeated patterns easier to notice without turning them into a score.
A month of raw values gives context for drift, recovery phases, and the conditions that move your numbers.
Design philosophy
"I wanted to see the actual shape of what was happening, not a number summarizing it. The crash after hot yoga. The rise after cold exposure. The drift during sleep. That shape was more useful than a verdict."
- the creator
Analysis appsReadiness score
HRVSparkRaw SDNN value
Analysis appsColor-coded verdict
HRVSparkNeutral sparkline
Analysis appsProprietary interpretation
HRVSparkHealthKit data in view
Analysis appsTell you what to do
HRVSparkShow you what happened
Who it is for
You are already tracking sleep, recovery, breathwork, training, cold exposure, or stress. You want a cleaner window into the signal.
You may use deeper analysis tools, but you still want one watch-face view that simply shows the raw data.
You do not need a product telling you whether today is good or bad before your feet hit the floor.
You care about the shape and the value. Everything else should earn its place.