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FatMax by Afasteryou

· v1.2.0
★★★★★ (3) ↓ 100 downloads 4 Free

About

FatMax % by afasteryou ======================= Train exactly in your personal FatMax zone. FatMax % shows in real time how close you are to your individual maximum fat oxidation rate (FatMax). * 100% = exactly at FatMax * 1%–99% = below or above optimum – fat burn drops as you move away * 0% = at or above Critical Power or Speed – fat metabolism nearly stops ------------------------------------------------------------ HOW IT WORKS 1. Take the afasteryou Powertest (paid, online) or automatically use our Powertest AI via Garmin Sync. Both provide your VO₂max and VLamax – essential for accurate substrate usage calculation. 2. Enter the code shown on your Garmin at: https://afasteryou.com/connect/ 3. It may take up to 10 minutes after activation before the data field updates. Until then, a pairing code will be shown. 4. Add the data field to a Running profile (uses speed) or a Cycling profile (requires power). 5. Start training and aim to stay close to 100% – that’s your personal fat-burning sweet spot. ------------------------------------------------------------ REQUIREMENTS * Cycling – requires a paired power meter * Running – works from speed and altitude; no power sensor needed * The field shows a pairing code until VO2max and VLamax are set * Works indoors as long as power (bike) or speed (run) is recorded ------------------------------------------------------------ DATA SYNC * Your metabolic data (VO2max, VLamax) is synced automatically every 12 hours * If you complete a new Powertest, updates are applied at the next sync ------------------------------------------------------------ ACCURACY Calculations are based on the metabolic model by Alois Mader (2003) and have been validated against laboratory gas exchange data in collaboration with MSH Medical School Hamburg (University of Applied Sciences) ------------------------------------------------------------ WHY USE IT * Train at the exact intensity that maximizes fat metabolism – ideal for endurance, recovery, or weight-loss phases * One clear number, smoothed with a 5-second moving average – easy to read even under effort * Complements your pace, heart rate, or power data for deeper training insight ------------------------------------------------------------ UPCOMING FEATURES * AI-based Powertest support for daily updated metabolic values ------------------------------------------------------------ OTHER PRODUCTS * **Carbs Burned** – tracks cumulative carbohydrate usage based on your personal physiology * **Training AI** – adaptive running and cycling training plans, synced via Garmin Training * **Activity AI** – post-session analytics for Fat, Carbs, VO2max, VLamax, Training Score, CdA, and even muscle and blood lactate simulation ------------------------------------------------------------ SUPPORT Setup guide and FAQ: https://afasteryou.com/fatmax Email: [email protected]

What's new

1.2.0 — Fresh Profile Data • Cached profile data now carries a version stamp. After an app update the field detects the mismatch and fetches your current profile right away instead of waiting for its next scheduled refresh. • It keeps displaying values while that refresh runs, so there is no gap in tracking. The new profile is picked up at your next activity start — numbers never jump mid-ride. • The field also re-checks for updated data during an activity. Until now it stopped asking as soon as it had a profile to work with. 1.1.0 — Refined Running Power Model • Running power on gradients has been re-derived from our own platform data: 219 outdoor runs from 184 athletes, cross-validated against two independent running power meter families and against heart rate. • The resulting gradient response matches the published reference curve of Minetti et al. (2002) — our data and the literature independently arrive at the same model, which is now what the data field uses. • Uphill and downhill sections are now weighted by the measured energy cost of running on a slope, rather than by lifting work alone. Carb burn on rolling and mountainous routes is noticeably more realistic. • Gradient is now averaged over the last 10 s of distance, making it far more robust against barometer noise on the watch. • Flat running is unchanged — identical values to the previous version. • On hilly routes your numbers will differ from 1.0.0. They now match the afasteryou web platform, which runs the same refined model. 1.0.0 — Major Update: Spline Calculation & Smarter Pairing • Fats are now computed via a server-fitted spline curve, so the values match the afasteryou web platform exactly — no more rounding drift. • Smarter pairing flow: 5 min → 10 → 20 → 40 → … re-checks after install. • View switches from "Requesting…" to live fatmax tracking automatically. • Added: D2 Mach 2/Pro, Edge Explore 2, Edge MTB, Forerunner 570, Instinct Crossover AMOLED, Venu 4 (41/45mm), Venu X1. 0.0.8 - Added support for Garmin Edge 550, Edge 850, Forerunner 970, and Fenix 8 devices. 0.0.7 – Activity AI Integration • Added Powertest AI via Garmin Sync – enables real-time carb tracking without a paid Powertest. • VO₂max and VLamax are now estimated automatically from Garmin data. (HF and Power required) • Updated pairing messages and improved background sync performance. • Syncs every 2 min or 10 min (device-dependent); checks for new Powertest (AI) data every 24 h. 0.0.6 – Bugfix for Background Data Visibility • Fixed an issue where the registered flag in background data was not correctly set, which could prevent the pairing code from being hidden as intended. • This bug only affected devices capable of background data handling. All other devices were unaffected. 0.0.5 – Improved messaging and error handling • Data field now displays “Requesting…” until a successful server connection has been made. The pairing code is shown only after the first verified platform request. • Fixed a bug where missing speed values in running activities could cause calculation issues. 0.0.4 – Added internal version tracking 0.0.3 – Improved compatibility with Garmin Edge devices by extracting workout data directly from the info object within compute() 0.0.2 – Fixed bug where readiness check used an incorrect reference 0.0.1 – First release – shows real-time FatMax percentage based on personal metabolic profile. Requires afasteryou Powertest and pairing via afasteryou.com/connect

Permissions

BackgroundUserProfileCommunications

Details

Compatible with 242 devices
Updated Aug 28, 2026
Developer website ↗
Open on apps.garmin.com ↗