Analyse a Garmin .fit file without uploading it

Your Garmin watch records every workout as a .fit file. You can take that file and analyse it in Lapline, in your browser, without sending it to anyone: training load, heart-rate zones, laps, records and trends.

Open Lapline Try it with sample data

Get the original file from Garmin Connect

On the Garmin Connect website (connect.garmin.com), open the activity. The mobile app doesn't offer this.
Open the gear menu at the top right and choose Export Original.
You get a .zip with the .fit file inside. Unzip it, then import the .fit into Lapline.

Or read it straight off the watch

Plug the watch into a computer with its USB cable. Its activities are in the GARMIN/Activity folder. In Chrome or Edge, Lapline's Import window has Connect device folder: point it at that folder once, and from then on one click imports anything new. In other browsers, choose the files from that folder by hand.

What you see

The session's timeline of heart rate and pace, with steady-state and cardiac-drift detection.
Per-kilometre laps with a heart-rate trace each, and the route coloured by heart-rate zone.
Time in each heart-rate zone, using the zones set on your watch.
Garmin's own training effect, VO₂ max and recovery time where the watch recorded them (marked as estimates).
Across all your files: training load against your 6-week baseline, trends, and personal records.

Why not just upload it somewhere?

A .fit file with GPS is a precise record of where and when you train, and it usually starts at home. Lapline reads it in your browser and keeps it in your browser's own storage on your device. There's no Lapline server and no account, so there's nothing to upload it to. The code is open source (MIT), so anyone can check.