You do not need to replace your Polar heart rate monitor. You need a better app to use with it. Fitiv connects directly to your Polar H10, Polar H9, or other Polar Bluetooth sensors and unlocks HRV analysis, TRIMP-based training load, and recovery scoring that Polar Flow does not offer — all while your hardware stays exactly the same.
The Polar Situation: Great Hardware, Limited Software
Polar makes some of the best heart rate monitors in the world. The Polar H10 is widely considered the gold standard for chest-strap accuracy, recommended by exercise physiologists and researchers for clinical-grade heart rate and HRV data. The electrode contacts, the comfortable strap, and the sub-millisecond RR-interval recording have made the H10 a benchmark device for over a decade.
Polar Flow — the app that comes with Polar devices — is where the experience falls short for serious athletes who want more from their hardware.
Polar Flow is a solid basic fitness logging platform. It records workouts, shows heart rate during sessions, and provides Polar's proprietary "Nightly Recharge" readiness metric on devices that support it. For athletes using a Polar watch (not just a heart rate strap), there are reasonable sleep tracking and basic training load features.
But for athletes using the Polar H10 as a chest strap with a phone or Apple Watch — which describes a large portion of H10 users — Polar Flow is primarily a workout log. It does not deliver:
- True HRV analysis from your RR-interval data in an actionable daily readiness score
- TRIMP or TSS-based training load management with acute/chronic load tracking
- Strength training with set-by-set logging, progressive overload analysis, and muscle group tracking
- GPS route recording integrated with your heart rate data
- A unified dashboard that synthesizes recovery, training load, and workout planning in one mobile-first interface
Fitiv does all of this — and your Polar H10 connects directly to Fitiv via Bluetooth.
Fitiv + Polar H10: What the Combination Unlocks
Clinical-grade HRV data in a training-intelligent app
The Polar H10's sub-millisecond RR-interval accuracy is the input. Fitiv's HRV analysis, readiness scoring, and training load calculation is the output. Together, they produce a system where you have the most accurate consumer-grade HR sensor available feeding the training intelligence layer that Polar Flow lacks.
When you pair your Polar H10 with Fitiv:
- RR intervals are recorded continuously during workouts for TRIMP-based training load calculation
- Overnight HRV trends (via Apple Watch when wearing both) feed the daily readiness score
- Every hard interval, tempo effort, and long endurance session accumulates into your acute and chronic training load — visible in your rolling load chart
Strength training your HR monitor was never designed for — but Fitiv makes work
The Polar H10 is excellent for cardio. Fitiv extends it into the gym. When you log a strength session in Fitiv wearing your H10, the heart rate data informs:
- How hard each set was relative to your max heart rate
- How quickly you recovered between sets
- The overall strain contribution of the lifting session to your training load
You can log every exercise, set, rep, and weight while your H10 records the cardiovascular stress in the background. This gives you a complete picture of your training that Polar Flow's basic workout log cannot provide.
GPS cardio tracking with your existing sensor
Fitiv records GPS routes for outdoor runs, rides, and hikes using your phone's GPS or Apple Watch — while your Polar H10 sends precise heart rate data via Bluetooth. The combination means you get accurate maps and pace data alongside the H10's gold-standard heart rate accuracy, with heart rate zones calculated from your personal threshold data.
What Polar Flow Does Better
In the interest of honesty: Polar Flow is the native home for Polar watch users who want full device integration. If you own a Polar Vantage M2, Grit X, or other Polar GPS watch (not just the H10 strap), Polar Flow integrates directly with that hardware in ways third-party apps cannot fully replicate.
Polar's Orthostatic Test — a validated HRV measurement protocol using a specific standing/lying sequence — is built into Polar watches and Polar Flow. This is a research-validated readiness assessment that Fitiv does not replicate.
For athletes who have years of training history in Polar Flow and rely on its long-term load charts and sport profile configurations, switching apps means starting a new history and losing the continuity of that data.
Polar's training pace zones and sport-specific profiles (swim, row, ski) are more configured in Polar Flow than in Fitiv, which is designed around running, cycling, and strength as primary training modalities.
Feature Comparison: Fitiv vs Polar Flow (with Polar H10)
| Feature | Fitiv + Polar H10 | Polar Flow + Polar Device | |---|---|---| | Polar H10 Bluetooth connection | Yes — direct | Yes — native | | HRV readiness score | Yes — daily actionable score | Partial (requires Polar watch with sensor) | | Training load (TRIMP/TSS) | Yes | Basic (Training Load Pro on premium) | | Acute / chronic load tracking | Yes | Yes (Polar devices) | | Strength tracking (sets/reps) | Yes | No | | GPS workout tracking | Yes (via Apple Watch or phone) | Yes (via Polar GPS watch) | | Apple Watch support | Yes — native | No | | Orthostatic Test | No | Yes (validated protocol) | | Sleep tracking | Yes (via Apple Watch) | Yes (via Polar watch) | | Recovery score | Yes | Yes (Nightly Recharge, device-dependent) | | VO2 max estimate | Yes | Yes (Polar devices) | | Workout builder | Yes | Yes | | Mobile-first design | Yes | Moderate | | Price | Free tier + from $4.99/month | Free (basic) / Polar Premium available |
The App Store Signal Worth Noting
Fitiv has the highest impression share of any competitor app for the search term "polar flow" in the App Store Search Ads ecosystem. This is not marketing language — it reflects that Apple's algorithm surfaces Fitiv as the most relevant third-party alternative for athletes searching for Polar Flow alternatives. The athletes running those searches are typically Polar H10 users who want more than Polar Flow offers: specifically HRV analysis, training load, and recovery scoring.
Fitiv is built for exactly that athlete.
Who Should Use Fitiv as a Polar Flow Alternative
- Polar H10 and H9 users who want HRV readiness and training load beyond what Polar Flow provides
- Athletes using a Polar chest strap with an Apple Watch who want a unified training and recovery platform
- Hybrid athletes who use Polar for cardio HR but also lift weights and want both tracked
- Self-coached athletes who want TRIMP/TSS training load management on a mobile-first app
- Runners and cyclists who want GPS, HR zones, and training intelligence without switching to a Polar GPS watch
Who Should Stay on Polar Flow
- Athletes using Polar GPS watches (Vantage, Grit X, Ignite) who rely on native device features
- Athletes who use Polar's Orthostatic Test protocol for readiness measurement
- Athletes with years of accumulated training data in Polar Flow who do not want to lose continuity
- Swimmers and rowers who need Polar Flow's sport-specific modes
Frequently Asked Questions
Does Fitiv connect to Polar H10 directly? Yes. Fitiv connects to the Polar H10 and other Bluetooth heart rate monitors directly via the Bluetooth Low Energy (BLE) protocol. You do not need Polar Flow or a Polar watch for Fitiv to receive heart rate data from your H10.
Can Fitiv read HRV from my Polar H10? Yes. The Polar H10 records RR intervals (the beat-to-beat timing that HRV is derived from) and transmits them via Bluetooth. Fitiv captures this data during workouts for training load calculation. Overnight HRV measurement in Fitiv uses Apple Watch's optical sensor. For athletes who want the H10's superior accuracy for overnight HRV, dedicated RR-interval recording protocols (sleeping in the strap) are possible but require a third-party app specifically designed for that use case.
Is Polar Flow free? The core Polar Flow app is free. Polar offers Polar Premium as a subscription with additional features including Training Load Pro. For athletes who want training load management, Polar Premium is comparable in functionality to Fitiv's premium tier — but Fitiv adds strength tracking, Apple Watch native support, and HRV readiness that Polar Premium does not offer.
Will Fitiv work with my Polar H9? Yes. The Polar H9 connects to Fitiv via Bluetooth in the same way as the H10. The H10 records RR intervals with greater precision, which matters for HRV analysis, but both devices work with Fitiv for workout HR monitoring and training load calculation.
Do I need an Apple Watch to use Fitiv with my Polar H10? No. Fitiv can use your Polar H10 as the primary heart rate source on its own. Apple Watch is not required. However, Apple Watch integration unlocks overnight HRV measurement and native wrist-based workout controls that enhance the Fitiv experience. For athletes without an Apple Watch, the Polar H10 alone is sufficient for workout tracking and training load.
What happens to my Polar Flow data if I switch? Your historical workout data remains in Polar Flow. You can export Polar data in TCX or GPX format. Fitiv will build its own training load history from the day you start using it — typically 2-4 weeks before the readiness score is fully calibrated to your fitness level. Your Polar hardware works exactly the same way, just connected to a different app.