Garmin heart rate and Hevy sets in one workout.

Half a workout in each app

You start a Strength activity on the watch to get real heart rate and training load. Then you log the actual sets in Hevy on your phone, because typing reps on a watch is slow. Garmin and Hevy have no official integration, so each app ends up holding half of the session.

After a sync, the Garmin activity holds the Hevy sets next to the heart rate the watch recorded. Sessions you only recorded on the watch show up in Hevy, and so do your Garmin weigh-ins.

Five flows, every 30 minutes

Each run goes through five flows in a fixed order. A and C use hevy2garmin, a community project. B, D and E are part of this project.

1. A
   Hevy workouts to Garmin activities. When the watch recorded the same session, the sets, reps and weights are merged into that recording. Garmin keeps the real heart rate and calories and does not gain a second, empty activity.
2. C
   Hevy routines to Garmin planned workouts, so you can follow them on the watch.
3. B
   Watch-only sessions to Hevy workouts. For strength sessions with no Hevy log to merge into. Garmin exercise names are matched to Hevy exercises, and anything without a confident match is named in the workout description instead of being dropped.
4. D
   Garmin weigh-ins to Hevy body measurements. It looks back a year, because weigh-ins are irregular.
5. E
   Exercise name repair. Fixes sets that show as “Choose an Exercise” in Garmin Connect. How that works.

Why the order matters

A runs before B. By the time B looks at Garmin, a session that started in Hevy already has its Hevy counterpart, so B skips it and nothing is imported twice. E runs last because it reads back what A wrote.

Loop prevention

A two-way sync without guards would copy the same workout back and forth. Four checks stop that:

Pairing ledger

B skips any Garmin activity that hevy2garmin has already paired with a Hevy workout, including sessions logged in Hevy hours later on the same day.

Overlap window

B skips any Garmin activity that starts within 45 minutes of an existing Hevy workout, or overlaps one in time. It also waits three hours after a session ends before importing it. This covers the gap before A records its pairing.

Cross-marking

When B creates a Hevy workout, it writes the pairing into hevy2garmin's ledger, so A never pushes it back to Garmin.

Local ledger

Every activity B has imported or skipped is recorded. Only failures are retried.

Exercise names that show up in Garmin

Merging Hevy sets into a watch recording used to leave every set reading “Choose an Exercise”, with a blank muscle map. The names were stored correctly. Garmin Connect ignored them because each set said it had been identified with zero confidence.

Before After flow E

Garmin's rep counting stores how sure it was about each movement. Sets pushed in from outside carried a value of 0.0, which Garmin Connect reads as “nothing identified”, even when the name next to it is correct:

{
  "category": "SQUAT",
  "name": "PISTOL_SQUAT",
  "probability": 0.0
}

Flow E restates the same sets at full confidence and changes nothing else. It only touches active sets that have a real category at zero confidence, so sets the watch detected itself are left alone. hevy2garmin 0.12 now does this for new merges. Flow E repairs activities merged before that.

Runs in the background

The installer ends by starting garmin-hevy-sync setup, which asks for what it needs and then turns on the schedule:

1. Hevy API key. Copy it from hevy.com/settings?developer. The API needs Hevy Pro.
2. Garmin sign-in. Your email, password and the code Garmin emails you, once. The password is not stored, only tokens that refresh themselves.
3. Body stats. Optional. They make the calorie estimates more accurate.
4. Schedule. Setup turns on the background run, every 30 minutes from then on.

Runs missed while the computer was asleep or off are caught up. To change the schedule yourself, use garmin-hevy-sync schedule install, remove or status.

Commands

gh-sync is a shorter alias for garmin-hevy-sync.

setup

Run the setup wizard again.

login

Sign in to Garmin again, for example after the sign-in expired.

sync

Run the flows now. --dry-run reports what would change without writing anything, --flows a b runs only those flows, and --every 30m keeps repeating.

status

Show what has been synced and the last run's summary.

doctor

Check both accounts and list your devices and recent activities.

logs

Show the log. Add -f to follow it.

unmapped

List Garmin exercises that have no confident Hevy match.

push-to-watch

Send planned workouts to the watch now.

schedule

install, remove or status for the background schedule.

--version

Print the installed version.

Privacy and safety

• It runs on your computer. Nothing leaves it except requests to Hevy and Garmin.
• Your Garmin password is used once, to sign in, and is not saved. The sign-in leaves refreshable tokens in ~/.garminconnect.
• The Hevy API key and settings live in one folder for your user account. Set GH_SYNC_HOME to use a different one.

  Linux

  ~/.config/garmin-hevy-sync

  macOS

  ~/Library/Application Support/garmin-hevy-sync

  Windows

  %APPDATA%\garmin-hevy-sync

• Flow A merges into the watch recording instead of replacing it, so the heart rate, training effect and body battery Garmin recorded stay as they were.
• sync --dry-run shows what a run would change without writing anything.
• When a run fails, for example because the Garmin sign-in expired, you get a desktop notification. To get a push on your phone instead, set GH_NOTIFY_URL to an ntfy-style URL.
• Keep two-factor authentication on. The emailed code is needed once, at sign-in.

Questions