Time in heart-rate zones from a .fit file
Open your .fit files in Lapline and see how long you spent in each heart-rate zone: for a single session, for a week, or over months, to check whether your easy days are really easy.
Which zones?
When your watch records a workout it also writes down your heart-rate zones as they were set on the watch, and how long you spent in each. Lapline uses those, so the numbers match what your watch and its app show: Zone 1 (warm up) to Zone 5 (maximum). To change your zones, change them on the watch or in its app; new workouts will use them.
What you can see
- Per session: time and share in each zone, a heart-rate density chart of every reading, and the route and timeline coloured by zone.
- Per lap: a zone-mix bar under each kilometre.
- Over time: Today shows your time in zone for the chosen range, and Trends shows each week's intensity distribution, so you can see whether you're training mostly easy (Zones 1–2) with a little hard work, or drifting into the middle.
- In the activity list: each session's zone split as a small bar, and its average heart rate coloured when it was hard (Zone 4 or 5).
What it needs
A .fit file from a watch that recorded heart rate. A .gpx file has no zones or zone times in it (and many .gpx exports have no heart rate at all), so zone breakdowns need the original .fit file. See how to get the original files for Garmin, COROS, Wahoo, Suunto, Polar, Zwift, Apple Watch and Strava.
Private by design
Lapline reads your files in your browser and keeps them on your device. There's no account and nothing is uploaded.