Google Pixel Watch uses Fitbit's health algorithms. Active Zone Minutes, Sleep Score, Daily Readiness, and skin temperature — what each measures and how it is calculated.
Google Pixel Watch (all generations) runs Fitbit's health and wellness algorithms through the Fitbit app. Understanding Pixel Watch metrics means understanding Fitbit's measurement framework, which differs from Oura, Garmin, and Whoop in several important ways.
Active Zone Minutes (AZM) is Fitbit's alternative to step counting. It counts time spent in heart rate zones (Fat Burn, Cardio, Peak) rather than steps, weighted by intensity. AZM aligns with WHO guidelines (150 minutes/week moderate or 75 minutes/week vigorous activity). One minute in Cardio or Peak zone counts double in AZM.
Fitbit's Sleep Score aggregates duration, sleep stages (deep + REM proportion), and restfulness. The algorithm weights deep and REM sleep more heavily than light sleep. Score categories: Excellent (90–100), Good (80–89), Fair (60–79), Poor (below 60).
Daily Readiness is Fitbit's recovery composite, analogous to Oura Readiness or Whoop Recovery. It incorporates recent activity load, sleep quality, and HRV. It is limited to Fitbit Premium subscribers. Compared to Oura, Fitbit's readiness algorithm weights recent activity recovery more prominently relative to HRV.
Pixel Watch tracks wrist skin temperature deviation from personal baseline during sleep. Displayed as a graph in the Health Dashboard. The same data underpins Fitbit's cycle tracking temperature feature, which detects the post-ovulation temperature rise. Absolute temperature readings are not shown — only deviation from baseline.