Video summary

Pixel Watch 3: Scientific Review (Best Android Smartwatch!)

Main summary

Key takeaways

Product Review

Product reviewed

Google Pixel Watch 3 (tested in 45mm and 41mm sizes) — an Android smartwatch focused on heart-rate accuracy, sleep staging, GPS, and newer health/readiness-type metrics.

Key features mentioned

  • Improved heart rate tracking

    • Tested during indoor cycling, running, outdoor cycling, and weightlifting
    • Compared against a reference Polar ECG chest strap (Polar H10); also used multiple test people

  • Sleep stage tracking

    • Compared against an EEG headband (zMAX ECG) for deep/light/REM stages over 6 nights
    • Notes that wake-time accuracy wasn’t the focus (EEG detects many short awakenings)

  • GPS tracking during cycling

    • Repeated the same commute routes multiple times (3x each direction) to judge consistency

  • Health metrics (“readiness” style scores)

    • 5 daily morning health metrics: HRV, breathing rate, skin temperature, oxygen saturation, resting heart rate
    • Also mentions exercise-related scores: target load and cardio load

  • Running features

    • Includes target heart-rate guidance/reminders during runs (user set a low target and was prompted to slow down)

Scientific testing results (main numerical outcomes)

Heart rate tracking (vs Polar H10 ECG)

  • Indoor cycling

    • 45mm: correlation r = 1.0
    • 41mm: correlation r = 0.99
    • Conclusion: very strong agreement; only minimal deviations

  • Running (multiple people)

    • Rafael: 45mm r = 1.0, 41mm “basically identical”
    • Teresa: 45mm r = 0.99, 41mm r ≈ 0.99
    • Notes: Teresa’s 45mm had a tiny artifact/deviation once; 41mm avoided it

  • Outdoor cycling

    • 45mm: correlation 0.97
    • 41mm: correlation 0.97 (slightly less deviation)

  • Weightlifting (hardest test)

    • 45mm: correlation 0.91
    • 41mm: correlation 0.93
    • But in practice: it missed many HR peaks in one session
    • Verdict: not recommended for weightlifting

Sleep stage tracking (vs zMAX EEG)

Across ~6 nights, using the concept of “% of stage agreement”:

  • Deep sleep: ~70% agreement
  • Light sleep: ~73% agreement
  • REM sleep: ~52% agreement (weakest stage; common for Google/Fitbit-type systems)
  • Awake time: ~48% agreement, but not emphasized due to EEG behavior

Overall: second-tier, not top absolute performer.

GPS tracking (cycling to/from work)

  • Acquisition speed: GPS lock generally quick
  • Accuracy: route shape was consistent, but there is high-frequency “jiggle/noise”
    • Could imply slightly inflated distance (needs deeper testing)
  • No major consistent advantage stated for one size; both look “pretty decent.”

Health metrics during illness (COVID period)

During the period the reviewer was sick:

  • Breathing rate: increased and stayed elevated longer
  • Resting heart rate: rose during illness and later normalized
  • HRV (heart rate variability): dipped during peak sickness then improved
  • Skin temperature: reportedly stayed normal (no fever)
  • Oxygen saturation: increased slightly; not strongly abnormal

The reviewer suggests it may detect impact of illness but calls for more baseline data.

Comparisons made (competitors)

Heart rate accuracy

  • Pixel Watch 3 is described as top-tier for Android, with results close to Apple Watches and near consistently strong Huawei devices
  • Compared to Pixel Watch 2:
    • Pixel Watch 3 shows clear improvement, especially for running and cycling
  • Weightlifting: Pixel Watch 3 is close to Pixel Watch 2 in performance and still not good enough to recommend for that sport

Sleep staging

  • Compared against “top” sleep trackers (examples mentioned):
    • Apple Watches, Oura Ring, Eight Sleep, Whoop/Nu app (“Nu app” name mentioned)
  • Pixel Watch 3 is placed in a second tier
    • Close to other Google/Fitbit products
    • Possibly slightly worse than Pixel Watch 2 in this reviewer’s sick-period test (though reviewer notes illness may bias results)

Running performance (apps/guidance)

  • Based on limited data, Pixel Watch 3 heart-rate running tracking is described as among the best
  • The 45mm version had the best correlation in the reviewer’s running test so far (single run / limited data)

Pros (as stated/implied)

  • Major improvement in heart-rate tracking, especially for running
    • Multiple correlations near 1.0
  • Sleep staging is consistent and “pretty decent”
    • Stronger on deep/light than REM (typical limitation)
  • Wear size fit improved
    • 45mm described as finally the “right size” for daily use
  • GPS tracking is usable and consistent
    • Some noise, but overall solid
  • New health/exercise scores (readiness-like system)
    • Appears to reflect illness-related changes (breathing rate, HRV, resting HR)

Cons (as stated/implied)

  • Weightlifting / peak HR capture is weak
    • Misses peaks in at least one session despite decent correlation numbers
  • REM sleep detection is a known weakness
    • Only about ~52% agreement vs EEG reference
  • GPS has “high-frequency noise”
    • Not very smooth; may slightly affect derived metrics like distance (not fully proven)
  • Sleep testing performed while sick
    • Reviewer believes this could bias sleep results downward
  • Suitability depends on platform
    • Best if you’re an Android user; Apple Watch is a strong alternative on iOS

User experience / daily-driver conclusions

  • Reviewer says Pixel Watch 3 is the first Pixel Watch they could see using as a “daily driver.”
  • Reason: better heart-rate tracking + still pretty decent sleep staging + 45mm comfort/fit
  • Running guidance: watch reminded the user to slow down when exceeding the set target heart-rate

Overall verdict / recommendation

Highly recommended for Android users who prioritize accurate heart-rate tracking (especially running/cycling) and want decent sleep staging.

Not recommended for weightlifting specifically, due to missed heart-rate peaks during sessions.

Sleep tracking is good but not the absolute best—REM remains the weak point.

Unique points mentioned about the product (consolidated)

  1. Improved heart rate accuracy (near-perfect correlations in cycling and running)
  2. Different performance patterns by sport: excellent for running/cycling, weak for weightlifting
  3. Deep/light sleep staging agreement ~70–73% vs EEG; REM ~52% (main weakness)
  4. Sleep results match typical Google/Fitbit algorithm behavior; possibly affected by being sick
  5. GPS cycling tracking is consistent but noisy/not perfectly smooth
  6. 5 morning health metrics tracked daily (HRV, breathing rate, skin temp, oxygen saturation, resting HR)
  7. Health scores appeared to reflect illness trends (breathing rate/resting HR/HRV)
  8. Exercise guidance via cardio load and target load; targets may feel low and may require longer calibration
  9. Running features include active heart-rate guidance (slow-down reminders)
  10. 45mm size is emphasized as the better “fit” for daily use

Speaker-specific views (only if distinct)

  • Primary reviewer (main tester):

    • Emphasized scientific HR accuracy improvements, sleep staging tiering, GPS noise, and weightlifting limitation
    • Also assessed recovery/health metrics during COVID

  • Teresa (ran and tested HR tracking):

    • Strong agreement while running; noted a small artifact/deviation on 45mm once
    • Felt one watch recorded her as going faster, but app comparisons showed results were close; possible unit/app differences

  • Rafael (ran and tested HR tracking; cycling):

    • Very happy with the watch; saw strong running agreement (45mm and 41mm)
    • Suggested Pixel Watch 3 may be slightly better than Pixel Watch 2; preferred Pixel Watch 3 (especially larger 45mm)

Original video