Fitiv + Polar H10: Medical-Grade HRV in Your Training App
The Polar H10 is widely regarded as the most accurate consumer heart rate monitor available — it uses an ECG-grade chest electrode that measures true beat-to-beat intervals (RR intervals), the foundation of accurate HRV measurement.
Fitiv Pulse connects directly to the Polar H10 and other Polar HR monitors via Bluetooth, giving you the accuracy of a clinical ECG sensor with the training intelligence of an AI fitness app.
Why Polar H10 Accuracy Matters for HRV
HRV (heart rate variability) is measured in milliseconds between heartbeats. Even a 10ms error in RR interval detection degrades the HRV calculation significantly.
| Sensor Type | Accuracy | Best For | |---|---|---| | Polar H10 (ECG chest strap) | ±1ms RR interval | HRV, high-intensity, cycling | | Apple Watch (optical PPG) | ±5-10ms at rest | Convenience, daily wear | | Wrist optical (generic) | ±10-30ms | Basic heart rate, not ideal for HRV |
For HRV-based training readiness, the Polar H10 is the gold standard. Fitiv uses these ultra-precise RR intervals to calculate your RMSSD score and daily readiness.
How to Connect Polar H10 to Fitiv
- Wet the Polar H10 electrodes (improves electrical contact)
- Strap around your chest at the base of your pectoral muscles
- Open Fitiv Pulse on your iPhone
- Go to Settings → Sensors → Bluetooth Devices
- Tap "Add Sensor" and select your Polar H10 from the list
- Pair and confirm — the connection is saved for future sessions
Tip: Fitiv remembers paired Bluetooth devices. On subsequent sessions, the H10 connects automatically when you start a workout.
Supported Polar Devices
- Polar H10 — Best choice. True ECG electrode, RR interval recording
- Polar H9 — Excellent accuracy, slightly older model
- Polar OH1 — Optical arm sensor (less accurate than H10 for HRV)
- Polar Verity Sense — Optical arm sensor
- Polar Vantage / Grit X — Syncs via Apple Health
Polar H10 vs Polar Flow
Polar Flow is Polar's native app. Here's why serious athletes choose Fitiv for training analysis:
| Feature | Polar Flow | Fitiv + Polar H10 | |---|---|---| | HRV readiness score | Basic | Advanced (RMSSD + 7-day trend) | | Training load | Basic effort score | TRIMP, TSS, RPE | | Recovery tracking | Limited | Full recovery score + sleep | | Strength training | No | Yes (sets, reps, PRs) | | VO2 max tracking | Yes | Yes | | Challenges & community | No | Yes | | AI coaching insights | No | Yes |
You don't need to abandon your Polar hardware — just add Fitiv for the training intelligence layer.
HRV Morning Protocol with Polar H10
For the most accurate HRV reading:
- Wake up, don't check your phone or get out of bed
- Strap on the Polar H10
- Open Fitiv and start a 5-minute HRV reading
- Lie still, breathe normally
- Fitiv captures your morning RMSSD and updates your readiness score
This "orthostatic-free" morning protocol is what endurance coaches recommend for consistent HRV baselines.
Frequently Asked Questions
Q: Does the Polar H10 work with Fitiv without the Polar app? A: Yes. Fitiv connects directly to the Polar H10 via Bluetooth, no Polar app required.
Q: Can I use my Polar H10 for swimming workouts? A: The Polar H10 is waterproof (IPX7), but Bluetooth doesn't transmit through water. For pool swimming, the H10 stores RR intervals internally and syncs after the session.
Q: How accurate is Apple Watch for HRV compared to Polar H10? A: At rest (overnight), Apple Watch optical HRV is reasonably accurate. During exercise or immediately post-workout, the Polar H10 is significantly more accurate due to its ECG-grade electrode.