Get in touch
Please include your iOS version, app version (Settings → About) and a screenshot — it dramatically speeds up triage.
oneplayer_app@outlook.comUsually within 48 hours (holidays may delay).
System requirements
- iOS 26 or later
- iPhone 11 or newer (HealthKit required)
- Recommended: Apple Watch Series 6+ for HRV and overnight HR
- ~80 MB storage (includes 90-day cache)
How to improve HSI accuracy
Wear Apple Watch overnight: the HSI algorithm depends heavily on overnight HR and sleep stages.
Wait 14 days for baseline: HSI is scored relative to your own baseline, which stabilizes after about two weeks.
In Settings → Data Sources, confirm all HealthKit permissions are granted.
What do Tier B / Tier C mean?
Tier S: HRV, RHR, sleep and activity all available — full weighted model is used.
Tier B: HRV is missing or unstable. Falls back to an RHR-based 3-dim model. Lower precision but still useful.
Tier C: Insufficient data — HSI is not emitted for the day. Check HealthKit permissions and Apple Watch wear time.
Subscriptions
Cancel: iOS Settings → Apple ID → Subscriptions → HeartStress → Cancel.
Refund: visit reportaproblem.apple.com — refunds are handled by Apple.
Restore: tap 'Restore Purchases' at the bottom of the paywall and sign in with your original Apple ID.