Where to Get FIT and GPX Files for Cycling Video Overlays

FIT (Flexible and Interoperable Data Transfer) is a compact binary activity format common on Garmin and many other bike computers. It can store speed, power, heart rate, cadence, altitude, distance, GPS, and timestamps in one file.

GPX (GPS Exchange Format) is an XML track format used by many mapping and fitness services. It usually provides route, elevation, and timestamps; speed may be recorded or derived from GPS. Sensor fields depend on the exporter.

• Garmin: download the original activity from Garmin Connect, or copy .fit files from the head unit over USB.
• Wahoo, Hammerhead Karoo, Bryton, Magene, and similar head units: export or sync activities as FIT.
• Zwift and other indoor platforms: export the completed ride as FIT when the platform offers it.
• Prefer the original FIT file. Converting FIT to GPX for convenience often drops power, cadence, or device-recorded speed.

• Strava: open the activity and export GPX (route and derived motion are common; sensor extensions vary).
• Komoot, Ride with GPS, and similar route services: export a timed GPX track.
• Garmin Connect GPX export: works for route-focused overlays, but may omit sensor fields that exist in the original FIT.
• Use GPX when you mainly need route, location, elevation, or compatibility with a GPX-only workflow.

• Choose FIT when you need recorded power, heart rate, cadence, wheel or device speed, and the most complete cycling sensor data.
• Choose GPX when route, elevation, and GPS-derived speed are enough, or when your platform only offers GPX.
• Ride Data Overlay shows a gauge only when usable samples exist in the file. Missing metrics cannot be reconstructed from GPS alone.

The Fitness app and Apple Health do not provide a direct FIT or GPX download. Ride Data Overlay is a browser app and cannot call HealthKit — there is no web API for Apple Health.

The practical workflow is indirect: record the ride on Apple Watch, then use an iPhone app that reads HealthKit directly (for example HealthFit or RunGap) and export a FIT file. Verify heart rate in the Ride Data Overlay preview after import.

Do not rely on the Health app “Export All Health Data” ZIP for heart-rate overlays. That export often aggregates workout heart rate into coarse windows, producing far fewer samples than HealthKit-connected apps.

Apple Watch has no built-in power meter. Power appears only if you connected an external sensor and the export chain retained it. Indoor rides may have heart rate but no GPS route.

• Embedded action-camera telemetry (GoPro, DJI, Insta360) inside the video file.
• Apple Health export ZIP, TCX, CSV, or other activity formats.
• Reading Apple Health or HealthKit from the browser without a separate exported FIT or GPX file.
• Inferring heart rate, power, or cadence that were never recorded in the activity file.
• Step count overlays — FIT exports vary by device and bridge app; step data is not reliably present in FIT files today.
• When calories or steps exist only as lap/session totals (typical Apple Watch HealthFit exports), Ride Data Overlay estimates cumulative values along the walk using lap boundaries and distance within each lap.