Fitbit’s Apple Health sync now moves data both ways: steps, sleep, workouts, and heart rate transfer from Fitbit to Apple Health, but HRV still doesn’t. Twelve years. That’s how long it took Google Health to write data back into Apple Health.

Google Health version 5.05 started rolling out August 2, 2026, and by the next day iOS users had the option most of them assumed was already there: a real two-way sync between Fitbit (or Pixel Watch) and Apple’s Health app. Steps, sleep, workouts, and vitals now flow both directions. HRV does not. Not because Google forgot, and not because of some petty platform turf war — because Fitbit and Apple Watch calculate HRV using two different formulas that don’t translate into each other.

If you own a Fitbit Air or a Pixel Watch and carry an iPhone, this update actually matters. Here’s what changed, what didn’t, and why the one metric most recovery-focused users care about is stuck on the sidelines.

Quick Verdict

What	Syncs to Apple Health?
Steps	Yes
Distance	Yes
Sleep stages/duration	Yes
Exercise/workout records	Yes
Heart rate	Yes
SpO2 / vitals	Yes
Heart Rate Variability (HRV)	No — formula incompatibility
Cardio Load / Daily Readiness (Google’s proprietary scores)	No

Bottom line: Update Google Health to 5.05, connect it under Partner Apps, and your Fitbit or Pixel Watch data will finally show up in Apple Health and any third-party app that reads from it. Your HRV trend line will not — that data stays siloed on whichever app collected it.

What Actually Shipped

Before 5.05, the relationship between the apps was one-way. Apple Health data (workouts logged elsewhere, manual entries) could flow into Google Health. Nothing flowed back out. If you wore a Fitbit and used any of the dozen iOS apps that pull from Apple Health — a nutrition tracker cross-referencing calorie burn, a coaching app checking recovery inputs — your Fitbit data simply wasn’t visible to them. People built entire cottage industries of $2 bridge apps just to move step counts across the gap.

9to5Google’s release notes coverage confirms the fix: version 5.05 rolled out on iOS starting August 3, with exercise records, steps, vitals, and sleep data now writing into Apple Health. MacRumors and gadgetsandwearables both independently confirmed the same rollout window and the same list of synced categories, along with the same gap: HRV doesn’t move.

Setup is buried a couple menus deep. Open Google Health, tap your profile icon, go to Partner Apps, then Apple Health, and grant the permissions it asks for. If you’d already connected the apps in the read-only direction, you may need to tap Review permissions to add the new write access — a few users reported the toggle not appearing until they force-quit and reopened the app.

This lands four months after we covered Google’s March 2026 firmware update breaking Pixel Watch tracking entirely — doubled step counts, missing SpO2, the works. Worth noting because it’s the same data pipeline that’s now supposed to feed Apple Health accurately. If your Pixel Watch numbers still look inflated on the Fitbit side, don’t expect Apple Health to fix them on arrival. Garbage in, garbage synced.

Why HRV Doesn’t Sync (And Won’t Anytime Soon)

Here’s the part that actually requires an explanation, because “Google turned it off” is not what happened.

Heart rate variability (HRV) doesn’t sync from Fitbit to Apple Health because the two platforms calculate it using incompatible formulas. Fitbit and Pixel Watch use RMSSD — the root mean square of successive differences between heartbeats — which is the standard nearly every recovery-focused wearable uses. Apple Health’s native HRV field expects SDNN — the standard deviation of all normal-to-normal beat intervals — a different calculation that captures a broader slice of autonomic activity. Writing an RMSSD number into a field built for SDNN wouldn’t just be imprecise. It would be wrong.

That distinction isn’t a Fitbit quirk. WHOOP, Oura, Garmin, and Samsung all use RMSSD too — Apple Watch is the outlier running SDNN as its native HealthKit metric. Every one of those platforms has the exact same syncing problem Fitbit does, which is part of why you’ve never seen WHOOP or Oura HRV numbers show up natively in Apple Health either.

Michael Tsai’s technical breakdown lays out the mechanics clearly, and it lines up with what Tech Times reported the same week: this is a genuine data-format wall, not a business decision Google could reverse with a toggle. Until Apple adds an RMSSD data type to HealthKit — or Google rebuilds Fitbit’s HRV pipeline around SDNN, throwing out over a decade of RMSSD baseline data in the process — your HRV trend stays wherever it was recorded. For Fitbit and Pixel Watch owners, that means the Google Health app. For iPhone-native tracking, that means whatever the Apple Watch collects, if you’re wearing one at all.

Cardio Load and Daily Readiness — Google’s own composite scores, which lean on HRV as an input — don’t sync either, for the same underlying reason.

What This Means If You Own a Fitbit Air on iPhone

If you’re running the Fitbit Air — the $99.99 no-subscription recovery band we reviewed this month — this update closes a real gap. Before 5.05, an iPhone user wearing a Fitbit Air had sleep, steps, and Cardio Load trapped in Google Health with no way to feed a third-party dashboard or a doctor’s HealthKit-connected portal without a workaround app. Now that data moves natively.

What doesn’t change: if HRV is the reason you bought a recovery band in the first place, you’re still checking it inside the Fitbit/Google Health app, not Apple Health. That was already true before this update — Fitbit Air’s HRV, Cardio Load, and Daily Readiness scores have always lived in Google’s own app, same as WHOOP’s recovery score lives in WHOOP’s app and Oura’s readiness score lives in Oura’s. This update doesn’t change where you check recovery data. It changes whether your steps and sleep duration are visible to everything else on your phone.

Does This Affect Your Existing Health Tracking Stack?

Short answer: only if you’re specifically relying on third-party apps that read Fitbit-originated data through Apple Health.

We covered iOS 26.4 back in April as a minor Apple Health release — Average Bedtime and Blood Oxygen Vitals restored, the anticipated native nutrition logging held back. Google Health 5.05 is a bigger practical change for anyone straddling both ecosystems, even though it’s an update to Google’s app, not Apple’s. It’s also a reminder that Apple Health’s real value on iPhone has always been as a data hub other apps write into and read from — and until now, an entire hardware category (Fitbit, Pixel Watch) was only half-connected to it.

If you use a nutrition app, a training log, or a coaching app that pulls step counts, sleep duration, or workout data from Apple Health, that data should now be more complete if you’re wearing a Fitbit device. If that app’s coaching logic depends on HRV or recovery scores, nothing has changed for you — those inputs were never going to route through Apple Health, and 5.05 doesn’t touch that.

Who Should Update Now

Update immediately if: you own a Fitbit Air, Fitbit Charge, or Pixel Watch, carry an iPhone, and use any app outside Google Health that reads from Apple Health — nutrition trackers, training logs, doctor portals, family sharing setups.

Update, but don’t expect much if: your only reason for connecting the apps was to see HRV or recovery scores in Apple Health. That gap isn’t closing with this release, and there’s no announced timeline for it to close at all.

Skip if: you don’t use any third-party apps that pull from Apple Health and you’re happy checking everything inside Google Health directly. The update won’t hurt you, but it also won’t change your day-to-day.

The Bottom Line

Google Health 5.05 fixes a genuinely dumb twelve-year gap — Fitbit data now writes into Apple Health, not just out of it. Steps, sleep, workouts, and vitals move freely as of the August 2-3 rollout. That’s a real, useful fix if you’re an iPhone user wearing Fitbit or Pixel Watch hardware.

HRV isn’t part of it, and won’t be until Apple or Google rebuilds how one of them calculates it. RMSSD and SDNN measure related but distinct things, and neither company is going to quietly convert years of baseline data to make a sync feature work. If recovery tracking is why you bought the hardware, keep checking it in the app that collected it. This update was never going to change that — it was only ever about the data that doesn’t need a translator.

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Google Health 5.05 began rolling out on iOS August 2-3, 2026, per coverage from MacRumors, 9to5Google, gadgetsandwearables, and Michael Tsai’s blog. Feature availability may vary by device and account region.