Heavy built its following with one of the cleanest gym-tracking interfaces on iOS — fast to load, easy to log, and free of unnecessary complexity. It does exactly what a lifting session needs. What it cannot do is tell you what your body needs before the session starts.
Fitiv is for athletes who want Heavy's ease of use and want it embedded in a complete training system — one that knows your HRV, your fatigue from last week's runs, and whether today is a day to push or pull back.
What Heavy Does Well
Heavy's design philosophy centers on removing friction from strength logging. You open the app, find your workout, and start logging. The interface is clean, quick, and does not get in your way during a session. For athletes who find more complex apps overwhelming, Heavy's minimalism is a genuine virtue.
Progress tracking in Heavy is visual and clear. Lift history, volume trends, and personal records are presented without excess complexity. Plate calculators and weight increments are handled smoothly. For gym athletes who just want a reliable log with good presentation, Heavy delivers.
Heavy's one-time purchase or low subscription cost is also genuinely competitive — if your only need is a gym log, it is well priced for what it offers.
What Athletes Find Missing in Heavy
No readiness data before you lift
Heavy records what you do. It cannot tell you what you should do based on how recovered you are. There is no HRV measurement, no overnight recovery score, no fatigue tracking. Your training history exists in isolation from your physiology.
Serious strength athletes increasingly understand that training quality matters more than training quantity. Going into a heavy squat session with poor recovery produces junk volume, not adaptation. Fitiv gives you a readiness score each morning so that decision is informed, not guesswork.
No cardio or outdoor activity tracking
Heavy is purpose-built for the gym floor. If you run, cycle, row, or do any outdoor training, you need a second app. The more training modalities you use, the more this fragmentation creates blind spots — your cycling fatigue is invisible when Heavy looks at your gym performance.
No training load across modalities
A weekly running load plus a three-day lifting schedule produces a specific cumulative stress. Heavy accounts for only the lifting portion. Fitiv's training load calculation combines all workout types — every session contributes to a rolling load metric that reflects your real fatigue state.
What Fitiv Adds
Daily HRV readiness — Overnight Apple Watch HRV data generates a morning readiness score. High readiness means it is a good day to hit heavy sets. Low readiness means reducing intensity or shifting to a recovery session protects adaptation rather than undermining it.
Recovery score — A composite of HRV trend, sleep quality, and accumulated training load, updated each morning. The recovery score answers the question Heavy cannot: is your body ready?
Training load (TRIMP/TSS) — Acute and chronic load tracked across all workout types. You can see whether your fitness is trending up, whether fatigue is accumulating, and whether you are approaching overreaching territory.
GPS cardio tracking — Running, cycling, rowing, and other cardio sessions tracked with full GPS, heart rate zones, pace, and post-workout load contribution.
Bluetooth HR monitor support — Polar H10, Wahoo TICKR, Scosche Rhythm+, and other BLE heart rate monitors connect directly to Fitiv for accurate HR and HRV data.
Apple Watch depth — Beyond basic logging, Fitiv uses Apple Watch for HRV measurement, real-time heart rate during rest periods, rest timer notifications, and wrist-based readiness scores.
Feature Comparison: Fitiv vs Heavy
| Feature | Fitiv | Heavy | |---|---|---| | Strength tracking (sets/reps/weight) | Yes | Yes | | Custom exercises | Yes | Yes | | Workout templates | Yes | Yes | | Progressive overload tracking | Yes | Yes | | Workout history and charts | Yes | Yes | | Apple Watch integration | Deep — biometrics + logging | Basic | | Plate calculator | No | Yes | | HRV readiness score | Yes | No | | Recovery score | Yes | No | | Training load (TRIMP/TSS) | Yes | No | | GPS cardio tracking | Yes | No | | Heart rate zones | Yes | No | | Bluetooth HR monitor support | Yes | No | | VO2 max tracking | Yes | No | | Sleep tracking integration | Yes | No | | Community challenges | Yes | No |
Who Should Switch from Heavy to Fitiv
Fitiv is the right Heavy alternative if:
- You do any cardio alongside your strength training and want one app for both
- You want to know if your body is ready to train hard before you load the bar
- You use Apple Watch, Garmin, or a Bluetooth HR monitor and want deep integration
- You want recovery and HRV data without adding a separate WHOOP or Athlytic subscription
Who Should Stay on Heavy
Heavy remains the better choice if:
- Your training is 100% gym-based with no cardio whatsoever
- You want the absolute minimum interface — no readiness dashboards, no charts beyond lift history
- You prefer a one-time payment model and want to avoid any subscription
Frequently Asked Questions
Can Fitiv replace Heavy and a separate recovery app? Yes. If you currently use Heavy for lifting and rely on WHOOP, Oura, or Athlytic for readiness, Fitiv consolidates both functions into one subscription. The combination of strength logging and HRV readiness in a single app is Fitiv's core proposition.
Does Fitiv import data from Heavy? Fitiv does not import historical workout data from Heavy. Your new Fitiv training history begins with your first session, and HRV baselines become reliable within 2–3 weeks of consistent morning readings.
How quickly can I log a set in Fitiv compared to Heavy? Fitiv's strength logging flow is designed for speed — tap exercise, enter reps and weight, confirm, rest timer starts. The in-session experience is comparable to Heavy in terms of how quickly you can move through sets. The additional features (readiness, load) are on separate dashboard screens, not in the logging flow.
Does Fitiv work without an Apple Watch? Fitiv primarily targets Apple Watch users but also supports Garmin devices and Bluetooth HR monitors. The strength tracking features work on iPhone alone; HRV readiness and heart rate tracking during workouts require a connected sensor.
What Bluetooth HR monitors work with Fitiv? Fitiv connects to any Bluetooth LE heart rate monitor, including the Polar H10, Polar H9, Wahoo TICKR, Wahoo TICKR FIT, Scosche Rhythm+, and most other BLE chest straps and arm bands. For strength training, pairing a Polar H10 gives you accurate heart rate between sets and during warm-up cardio.
