Sensors

Active Metrics connects directly to Bluetooth training sensors from the watch — no phone required during the workout. Sensors connect automatically when a workout starts and disconnect when it ends.

What’s supported

• Stryd foot pod — running power, cadence, speed, and stride length. Wind-capable pods (Stryd Wind / Next Gen) also stream apparent wind speed and air power; on older pods those fields simply show as unavailable.
• Cycling power meters — power, plus crank cadence if the meter broadcasts it too.
• Cycling speed & cadence sensors — crank cadence. Wheel-magnet speed isn’t used; GPS drives outdoor speed.
• Smart trainers and treadmills (FTMS) — indoor bikes provide power, cadence, speed, and distance; treadmills provide speed and distance.

Two things pair elsewhere: heart-rate straps already paired with your watch work automatically — don’t pair them here. And generic (non-Stryd) running foot pods aren’t recognized yet, so they won’t appear in the scan.

Pairing

On the watch, open Settings → Sensors → Add Sensor. The first scan triggers the system Bluetooth permission prompt — sensors can’t work without it (if you declined, turn it back on under Settings → Active Metrics on the watch). Wake the sensor so it advertises — pedal a few strokes, or tap your Stryd — then tap it in the list to pair. The scan gives up after 30 seconds; wake the sensor and hit Scan Again.

Two pairing gotchas, straight from the field:

• If the sensor is also paired under watchOS Settings → Bluetooth → Health Devices, remove it there first — otherwise the OS holds the connection and Active Metrics can’t reach it.
• An FTMS machine first appears as an indoor bike; the app tells bikes and treadmills apart on first connection and corrects itself automatically.

Tapping a paired sensor shows what it reads, its battery level (flagged red below 15% — the pre-start screen warns you too, so you can charge before a long run), when it last connected, and a Forget Sensor button.

Which fields sensor data feeds

Sensor readings drive the same fields you lay out in Data Screens:

• Stryd → Power (with Air Power and Wind on wind-capable pods), Cadence, Stride Length — plus speed, pace, and distance when it’s the recording source (below).
• Cycling power meter → Power (and Cadence on dual-sensing meters), including average, max, normalized power, and power zones.
• Cycling speed & cadence sensor → Cadence.
• FTMS indoor bike → Power, Cadence, Speed, Distance.
• FTMS treadmill → Speed and Distance for indoor runs — no more guessing from wrist swing.

Power from a pod is lightly smoothed (about a 3-second window) for a steadier on-screen number.

When sensor data wins

While a sensor is connected and streaming, its readings take priority over the watch’s own estimates for the fields it covers. Every reading has a 3-second freshness window — if the sensor drops mid-workout, fields fall back to the watch’s wrist/GPS values instead of freezing on a stale number, and come back to the sensor when it reconnects.

What gets recorded to Apple Health follows the same idea, decided once at workout start:

• Runs with a Stryd — Stryd is the authoritative source for distance and power (requires Health write access for both). Distance falls back to GPS during dropouts; power leaves an honest gap.
• Indoor runs on an FTMS treadmill — the treadmill drives distance.
• Indoor cycling on an FTMS bike — the bike drives distance and power.
• Outdoor cycling with a power meter — GPS deliberately keeps driving distance; the meter’s power still feeds the live fields, averages, zones, and alerts.

Mid-workout drops

If a sensor drops for more than a few seconds during a workout, a banner tells you, and the watch keeps retrying in the background for as long as the workout runs. You’ll get a second banner when it reconnects. Quick blips reconnect silently.

Something not connecting that should? Check Troubleshooting or email [email protected].