All formulas, model parameters, sport-specific data and scientific sources behind the generator.
Without your own measurement, HRmax is estimated from age and — optionally — sex:
Tanaka provides more accurate estimates than the classic "220 − age" rule. Gulati was validated on over 5,000 women. A self-measured value always takes precedence.
All intensity values in this app are expressed as % of heart rate reserve (HRR). The Karvonen formula (1957) converts them to a target HR:
Mono-exponential approach with asymmetric time constants (τ_up < τ_down), auto-correlated noise (AR(1), φ = 0.85) and cardiac drift (Coyle & González-Alonso 2001). Trained individuals have smaller τ values (Imai et al. 1994). A deterministic PRNG produces the same curve for identical inputs.
| Level | % HRR | Zone | Application |
|---|---|---|---|
| Easy | 35–68 % | Z1–Z2 | Technique, warm-up, recovery |
| Moderate | 42–78 % | Z2–Z3 | Endurance base, light sparring |
| Normal | 50–88 % | Z3–Z4 | Regular training, Randori |
| Hard | 57–94 % | Z4–Z5 | Intense sparring, intervals |
| Maximum | 62–100 % | Z5 | Competition, tournament |
Aerobic TE: TRIMP mapped to 0–5 (Firstbeat 2017). Anaerobic TE: quadratic weighting above 80% HRR (Böning 1984).
Energy expenditure: Swain & Franklin (2002). Fat oxidation crossover: Brooks & Mercier (1994).
| Field | FIT-Nr. | Encoding |
|---|---|---|
| avg / max / min HR | 15 / 16 / 56 | bpm (uint8) |
| total_calories | 11 | kcal (uint16) |
| total_training_effect | 24 | ×10 (uint8) |
| training_stress_score | 35 | ×10 (uint16) |
| intensity_factor | 36 | ×1000 (uint16) |
| threshold_heart_rate | 27 | bpm (uint8) |
| time_in_hr_zone[0–4] | 65–69 | ms (uint32) |
| user_profile | Global 3 | age, sex, weight, HRmax, resting HR |
| zones_target | Global 7 | HRmax, LTHR, hr_calc_type=HRR |
The file is finalized with a correct CRC-16 and created entirely locally in the browser — no data is transmitted.
Karvonen J et al. (1957). Ann Med Exp Biol Fenn 35(3):307.
Tanaka H, Monahan KD, Seals DR (2001). J Am Coll Cardiol 37:153.
Gulati M et al. (2010). Circulation 122(2):130.
Banister EW (1991). Physiological Testing of the High-Performance Athlete. Human Kinetics.
Firstbeat Technologies (2017). Training Effect. White Paper.
Allen H, Coggan A (2003). Training and Racing with a Power Meter. VeloPress.
Seiler S, Kjerland GØ (2006). Scand J Med Sci Sports 16(1):49.
Swain DP, Franklin BA (2002). Med Sci Sports Exerc 34(1):152.
Brooks GA, Mercier J (1994). J Appl Physiol 76(6):2253.
Imai K et al. (1994). J Am Coll Cardiol 24(6):1529.
Coyle EF, González-Alonso J (2001). Exerc Sport Sci Rev 29(2):88.
Garmin (2024). FIT SDK Profile.xlsx, Version 21.x.