Garmin & Apple Watch — live sync

Every workout
tells a story.

Charmin turns your raw device data into performance intelligence — and makes training social. Sync, analyze, and compete with your crew.

Free to join. Bring your own Garmin.

28-day
rolling competition window
2 devices
Garmin + Apple Watch
5 metrics
steps, HRV, pace, sleep, cadence

Built for athletes who want to go deeper.

Not just a data dump — every metric is connected to help you understand the full picture of your training.

Unified device sync

Pull in every run, ride, and workout from your Garmin device and Apple Watch automatically. One source of truth for all your training data.

Efficiency analytics

Track your efficiency score — speed per heart rate beat — to measure true fitness gains over time, not just pace. See trends across every training block.

Sleep × performance

Correlate your sleep stages, HRV, and SpO₂ with next-day run quality. Understand how recovery drives performance before you lace up.

Social leaderboard

Compete on a rolling 28-day leaderboard with friends. Rankings are based on efficiency score so effort always beats raw speed.

Core metric

The efficiency score.

Charmin ranks athletes by efficiency — speed divided by heart rate. Not by who runs fastest, but by who runs smartest. A 5:30/km pace at 140bpm beats a 5:00/km pace at 175bpm every time.

score = (km/h ÷ avg_hr) × 100

Ready to start training smarter?

Connect your devices and join the leaderboard.