💡 Quick Answer
The sleep trackers with the best integration are Apple Watch (native to Apple Health), Oura Ring, WHOOP, Garmin, Withings, Eight Sleep and Ultrahuman, which all write sleep to Apple Health and Health Connect. Fitbit and Pixel Watch joined them in August 2026, when the Google Health app gained two-way Apple Health sync.
- Sleep duration and stages sync almost everywhere. HRV and proprietary scores often do not.
- Oura Readiness, WHOOP Recovery and Garmin Body Battery never reach Apple Health.
- Eight Sleep and Ultrahuman export HRV to Apple Health; Oura, WHOOP and Garmin do not.
- On Android, the hub is Health Connect, not Google Fit.
If you track sleep with one device and train with another app, the question that matters is not "does it track sleep?" but "does the data leave the device's own app?" This guide answers that for the nine most common sleep trackers, with what is shared, what stays locked, and how to connect each one.
First, a Note on Names: Google Fit, Health Connect and Google Health
Google's naming has changed several times, which is why searches still mention "Google Fit":
- Google Fit is being retired. New integrations no longer target it.
- Health Connect is the on-device health data hub on Android, built into Android 14 and later. It plays the same role Apple Health plays on iPhone. For background, see our Apple Health vs Health Connect guide.
- Google Health is the new name of the Fitbit app, renamed in May 2026. It is the companion app for Fitbit devices and Pixel Watch.
From August 3, 2026, Google Health version 5.05 or later on iPhone syncs two-way with Apple Health. These types go both ways: steps, distance, floors, active calories, VO2 max, workouts and routes, sleep sessions and stages, heart rate, resting heart rate, SpO2, respiratory rate, blood glucose, weight, body fat, nutrition, water and cycle tracking. HRV, skin temperature and mindfulness are read-only into Google Health: they come in from Apple Health but Fitbit's own values are not written back. To send Fitbit data to Apple Health, open Google Health and go to Profile → Partner apps → Apple Health; to pull Apple Health data in, use Connections → Apps and services → Apple Health.
Sleep Tracker Integration Comparison (2026)
"Writes sleep" means the device's app saves sleep sessions into the platform where other apps can read them.
| Tracker | Type | Writes sleep to Apple Health? | Writes to Health Connect? | What's shared | What stays locked in the app |
|---|---|---|---|---|---|
| Oura Ring | Smart ring | ✓ Yes | ✓ Yes | Apple Health: sleep stages, heart rate, respiratory rate, steps, active energy, workouts. Health Connect: sleep sessions, heart rate, steps, SpO2 | HRV (to Apple Health), Readiness score, temperature |
| WHOOP | Screenless band | ✓ Yes | ✓ Yes | Sleep, resting heart rate, respiratory rate, SpO2, workouts; steps and calories on Health Connect | HRV, Recovery score, Strain |
| Apple Watch | Smartwatch | ✓ Native | ✗ No (iPhone only) | Sleep stages, heart rate, HRV, respiratory rate, SpO2 (where available), wrist temperature, workouts | Nothing significant; Apple Health is its home |
| Fitbit / Pixel Watch (Google Health) | Tracker / smartwatch | ✓ Yes (Google Health v5.05+, since Aug 2026) | ✓ Yes | Sleep sessions and stages, heart rate, resting HR, SpO2, respiratory rate, steps, workouts | HRV and skin temperature are not written back to Apple Health; Sleep Score, Daily Readiness and Cardio Load are Google's own scores and have no Apple Health or Health Connect type |
| Samsung Galaxy Ring / Watch | Ring / smartwatch | ✗ No native sync (Samsung Health is Android only) | ✓ Yes, via Samsung Health | Sleep sessions and stages, steps, heart rate, SpO2, workouts, body composition | Energy Score, Sleep Score and sleep coaching (Samsung's own scores) |
| Garmin | Smartwatch | ✓ Yes, one-way (needs Garmin Connect open) | ✓ Yes, one-way | Sleep with stages, steps, distance, heart rate, workouts, active and resting energy, floors, body fat | Body Battery, Sleep Score and HRV Status: Garmin does not write HRV to Apple Health |
| Withings (Sleep Analyzer / ScanWatch) | Under-mattress mat / hybrid watch | ✓ Yes (open the Withings app to sync) | ✓ Yes | Sleep with stages, heart rate, steps, distance, calories, weight, body composition, VO2 max, blood pressure | HRV (used only inside Withings' Sleep Score) and the Sleep Score itself |
| Eight Sleep | Smart mattress cover | ✓ Yes | ✓ Yes | Sleep stages, heart rate, HRV (rMSSD), respiratory rate | Sleep Fitness Score and Autopilot insights |
| Ultrahuman Ring | Smart ring | ✓ Yes | ✓ Yes | Sleep stages, heart rate, HRV, skin temperature, SpO2 (both platforms) | Recovery Score, Sleep Index and Movement Index (Ultrahuman's own scores) |
The pattern is consistent: raw measurements (sleep time, stages, heart rate) travel well, while the scores each company builds on top of them stay inside the company's app. Apple Health and Health Connect have no data type for "Readiness" or "Recovery", so even an open company has nowhere to put them.
How to Connect a Sleep Tracker on iPhone
Permission is granted from the tracker's app, then managed in the Health app.
- Open the tracker's app (Oura, WHOOP, Garmin Connect, Withings, Google Health, etc.) and find its Apple Health or Partner apps / Integrations setting.
- Turn it on. iOS shows a permissions sheet: switch on Sleep plus any heart rate, respiratory rate or HRV types offered.
- To check or change it later, open the Health app, tap your profile picture, then Apps (under Privacy), and pick the tracker. You can also go to Browse → Sleep → Data Sources & Access.
- Open the tracker's app once after waking. Garmin and Withings in particular push data when their app syncs, not in the background.
How to Connect a Sleep Tracker on Android
- In the tracker's app, find the Health Connect option (WHOOP: More → Account & Settings → Integrations; Withings: Profile → Export health data to Health Connect).
- Approve the permission screen, making sure Sleep is allowed to be written.
- To review it, open Settings → Security & privacy → Health Connect → App permissions (the path varies slightly by phone maker) and select the app.
- Grant read access for sleep to any app that should use the data, such as your training app.
Why Your Sleep Data Doesn't Match Across Apps
Seeing 7h 12m in one app and 6h 48m in another is normal. Three things cause it:
- Different algorithms. Rings, wrist devices and mattress sensors measure different signals and use their own models to decide when you fell asleep and which stage you are in. None of them is a lab sleep study, and the same night can be scored differently.
- Duplicate sources. If you wear an Apple Watch and an Oura Ring, both write a sleep session for the same night. An app that reads every source may show inflated or overlapping totals.
- Apple Health's Data Sources priority. When several sources record the same type, Health uses the one at the top of the list for its own totals. New apps are added at the top automatically, so installing a new tracker can quietly change which device "wins". Fix it in Health → Browse → Sleep → Data Sources & Access → Edit and drag your preferred tracker to the top.
The practical fix: pick one primary sleep tracker, put it first in the priority list (or give only it sleep write access on Health Connect), and compare trends over weeks rather than single nights. Our sleep hygiene guide for athletes covers what to change once your data is reliable.
How to Choose a Sleep Tracker by Integration
Best for iPhone
Apple Watch writes everything natively, including HRV. If you prefer not to sleep in a watch, Oura exports the broadest sleep data of the subscription wearables, minus HRV and Readiness.
Best for Android
Pixel Watch or Fitbit via Google Health, or Samsung Galaxy Ring / Watch via Samsung Health, both of which write to Health Connect. If you might switch to iPhone later, note that Samsung Health has no native Apple Health path, while Google Health now does.
Best no-wearable option
Eight Sleep (mattress cover) or the Withings Sleep Analyzer (under-mattress mat). Both sync to Apple Health and Health Connect. Eight Sleep also exports HRV. Withings users report needing to open the app for data to appear in Apple Health.
Best for HRV and recovery
Decide whether you want recovery insights or recovery data. WHOOP and Oura give polished recovery scores, but those scores and their HRV stay in their apps; see our WHOOP vs Oura comparison. If you want HRV available to other apps, Apple Watch, Eight Sleep and Ultrahuman export it. For more on rings, read our smart rings guide.
How UltraFit360 Uses Your Sleep Data
UltraFit360 has bi-directional sync with Apple Health and Google Health Connect, so it can read the sleep, heart rate and HRV your tracker shares there, whichever device you use. That recovery data feeds the weekly AI coaching report, which looks at sleep and recovery trends alongside your training. Because it reads from the health hub, it can only use what your tracker exports, so the table above also shows what UltraFit360 can see. See all features.
Frequently Asked Questions
What connected sleep technology integrates with Apple Health or Google Fit?
Apple Watch, Oura Ring, WHOOP, Garmin, Withings, Eight Sleep, Ultrahuman and Fitbit or Pixel Watch (through the Google Health app) all write sleep data to Apple Health. On Android, Google Fit is being retired and Health Connect is the hub; Oura, WHOOP, Garmin, Google Health, Samsung Health, Withings, Eight Sleep and Ultrahuman all write sleep to Health Connect.
Which sleep trackers are known for good integration capabilities?
Apple Watch has the deepest Apple Health integration because it writes natively. Among third-party devices, Eight Sleep and Ultrahuman stand out because they also export HRV, which Oura, WHOOP and Garmin keep inside their own apps. Oura and WHOOP still export sleep stages or sleep sessions, heart rate and respiratory rate to both platforms.
What home fitness tech syncs with Apple Health or Google Fit?
Beyond wearables, Withings smart scales and the Withings Sleep Analyzer mat sync through the Withings app to Apple Health and Health Connect, and the Eight Sleep Pod writes sleep stages, heart rate, HRV and respiratory rate to both. Google Fit is being retired, so on Android look for Health Connect support.
Does Fitbit / Google Health sync with Apple Health?
Yes, since August 3, 2026. The Fitbit app was renamed Google Health in May 2026, and version 5.05 or later on iPhone syncs two-way with Apple Health, including sleep sessions and stages, heart rate, resting heart rate, SpO2, steps and workouts. HRV, skin temperature and mindfulness only flow from Apple Health into Google Health. To send Fitbit data to Apple Health, go to Profile, Partner apps, Apple Health; to pull Apple Health data into Google Health, go to Connections, Apps and services, Apple Health.
Does WHOOP send HRV to Apple Health?
No. WHOOP exports sleep, resting heart rate, respiratory rate, SpO2 and workouts to Apple Health, but HRV and the Recovery score stay in the WHOOP app.
Why does my sleep data not match between apps?
Each device uses its own sleep-staging algorithm, so the same night can be scored differently. If two devices both write sleep to Apple Health, Health uses the Data Sources priority order to decide which one counts, and other apps may read a different source or both. Pick one primary sleep source and move it to the top of the list.
UltraFit360 brings your workouts, nutrition and wearable data together. See how the AI fitness tracker works with Apple Health and Health Connect.
Put Your Sleep Data to Work
Sync Apple Health or Health Connect with UltraFit360 and get recovery-aware training in your weekly AI coaching report.