fitbit
Pick Fitbit if
- Simplicity over data depth
- Google ecosystem and one-click OAuth
- ECG + AFib on the wrist matter
Fitbit vs Garmin
Fitbit aims for simplicity. Garmin aims for completeness. Fitbit Charge or Pixel Watch reads sleep, HRV, SpO2, VO2max, ECG out of the box. Garmin watches add Body Battery, 24/7 stress, training load — Garmin's OAuth API is not open to us yet, so you upload a GDPR export until then.
fitbit
22/33signals its devices cover
Daily-wear watch + scale
vs
GARMIN
27/33signals its devices cover
Athletic / outdoor watch
QUICK VERDICT
If clarity matters more than data depth, Fitbit. If you want every signal MyBodyAI can read from a single device, Garmin — even with manual upload until Garmin's OAuth API opens to us. Among the providers you can connect today, Garmin is the only source of Body Battery and one of two that deliver a daytime stress channel, because Oura connects over OAuth and reads its own. Both feed the autonomic balance and morning energy indices. Amazfit exposes stress in its API as well, but that integration is still waiting on the vendor.
COVERAGE BY CATEGORY
Where each brand actually wins
Per-category breakdown of health signals exposed by each vendor's developer API. The number is breadth, not quality.
SIGNAL BY SIGNAL
The full matrix
| Signal | Fitbit | Garmin |
|---|---|---|
| Heart & Vitals | ||
| Resting HR | ✓ | ✓ |
| HRV | ✓ | ✓ |
| SpO2 | ✓ | ✓ |
| Respiratory Rate | ✓ | ✓ |
| Skin Temperature | ✓ | ✓ |
| Body Temperature | — | — |
| Blood Pressure | — | ✓ via Index BPM |
| ECG recording | ✓ | ✓ |
| AFib detection | ✓ | ✓ |
| Vascular age | — | — |
| Sleep | ||
| Sleep duration | ✓ | ✓ |
| Sleep stages | ✓ | ✓ |
| Sleep score | ✓ | ✓ |
| Sleep efficiency | ✓ | — |
| Sleep apnea index | — | — |
| Activity | ||
| Steps | ✓ | ✓ |
| Active minutes | ✓ | ✓ |
| Calories | ✓ | ✓ |
| Activities | ✓ | ✓ |
| Floors climbed | ✓ | ✓ |
| Distance | ✓ | ✓ |
| Fitness & Recovery | ||
| VO2max | ✓ | ✓ |
| Training load | ✓ | ✓ |
| Recovery / Readiness | ✓ | ✓ |
| Body Battery | — | ✓ |
| Stress (continuous) | ✓ | ✓ |
| Cardiovascular age | — | — |
| Body Composition | ||
| Weight | ✓ via Fitbit Aria Air | ✓ via Index S2 |
| Body fat % | — | ✓ via Index S2 |
| Muscle mass | — | ✓ via Index S2 |
| Hydration | — | ✓ via Index S2 |
| Bone mass | — | ✓ via Index S2 |
| Visceral fat | — | — |
Verified against vendor developer documentation and MyBodyAI backend code. This counts what a brand's API exposes, which is not the same question as what one device measures: the device catalog scores each model's own hardware, so its numbers differ.
Current Fitbit models Google Fitbit Air (2026), Google Pixel Watch 4 (2025), Google Pixel Watch 3 (2024), Fitbit Charge 6 (2023), all 8 Fitbit devices
Current Garmin models CIRQA Smart Band (2026), Forerunner 170 (2026), Forerunner 70 (2026), Forerunner 570 (47mm) (2025), all 28 Garmin devices
WHICH ONE FOR YOU
Pick the one that matches your priority
GARMIN
Pick Garmin if
- Body Battery and 24/7 stress matter
- You're fine uploading a GDPR ZIP weekly until OAuth opens
- Multi-week battery life and outdoor GPS
fitbit+GARMIN
Pick both if
- Garmin watch for the full signal stack
- Garmin Index S2 for body fat and muscle mass
- Once Garmin OAuth opens, Fitbit becomes optional
FAQ
Frequently asked questions
Should I choose Fitbit or Garmin?
For most people it is one or the other. Both are daily-wear devices that track the same core things, heart rate, sleep and activity, so wearing both is redundant. Use the matrix above to pick the one that wins the categories you care about.
Which one tracks more health signals?
Fitbit tracks 22 of the 33 signals I compare, Garmin tracks 27. The matrix above breaks it down by category, and they often win different categories.
Is it worth switching from Fitbit to Garmin?
Only if Garmin wins the categories you actually care about. If you already own Fitbit and it covers your main goal, the upgrade is rarely worth it. The matrix above shows exactly what changes.
How did you compare Fitbit and Garmin?
From each brand's official spec sheets and support pages, cross-checked against independent hands-on reviews (DC Rainmaker, the5krunner, Tom's Guide). Signal-level edge cases are noted in the matrix, not hidden behind a single check mark.
WHERE TO BUY
Check prices at the source
Links to each vendor's store. None of them changed any pick above.
MORE COMPARISONS
Explore other pairs
OPTIONAL — IF YOU WANT MORE
Want one place that merges both feeds?
MyBodyAI is what I build with these signals — it pulls from any combination of the brands above and derives Biological Age and 12 health indices from the raw numbers. Free to try, no card. It's optional — the comparison above stands on its own.
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