Hey 👋 I'm Joel, solo dev behind RHRSpark (and its sister app HRVSpark). After launching HRVSpark — which puts raw HRV data on your watch face — the most common request was: "Can you do the same thing for resting heart rate?" The problem is that "resting heart rate" means different things in different apps. Apple gives you a single daily number. Other apps calculate their own version. None of them explain what data went in or what was excluded. RHRSpark takes a different approach: two data sources, fully transparent. For short-term (8H/24H), it uses only heart rate samples that Apple specifically labeled as "sedentary" — bucketed into 5-minute intervals. When there's no qualifying data, you see a gap, not a guess. For long-term (7D/30D), it displays Apple's own daily resting heart rate directly. No transformation, no reinterpretation. You always know exactly what you're looking at. That's the whole point. $2.99 one-time Pro unlock. No subscription. No account. I'd love to hear: - Do you track your resting heart rate? What do you currently use? - Is the two-source transparency useful or confusing? - Which time window matters most to you?

RHRSpark

Your resting heart rate. Raw. Beautiful. On your wrist.

Your resting heart rate. Raw. Beautiful. On your wrist.