Big news for anyone in the Android and Fitbit world. Google Health is now a first-class data source in IntervalCoach, so the wellness and workouts recorded by your Fitbit, Pixel Watch or any Wear OS device can feed the coaching engine directly.
Google Health Connect is the official successor to the old Fitbit Web API, and it's how modern Fitbit devices, including the new Fitbit Air, expose their data. If you've picked up one of these, this is the path that brings your sleep, recovery and training into IntervalCoach: one connection in Settings, no third-party scripts.
Connect it under Settings → Integrations to turn it on. It's available on the Pro and Max plans.
What the connection reads
Your daily coaching now picks up the full wellness picture from Google Health:
- Heart rate variability — overnight HRV, the single most informative recovery signal we have.
- Resting heart rate — your morning RHR, elevated when you're not fully recovered.
- Respiratory rate — breaths per minute during sleep, another autonomic marker.
- Blood oxygen (SpO₂) — persistent drops can flag altitude adaptation or illness.
- Skin temperature — overnight deviation from your baseline, the same signal Whoop and Apple Watch track.
- Sleep duration and phase breakdown — total hours plus REM, deep and light sleep, time awake and sleep efficiency. A 7-hour night with 30 minutes of deep sleep and a 7-hour night with 2 hours of deep sleep say very different things about recovery.
- VO₂ Max — your cardio fitness estimate, a slow-moving indicator of aerobic fitness that complements your eFTP progression.
- Body weight and body fat percentage — from any connected scale that reports into Google Health.
And it's not just wellness. Your workouts sync too. Activities recorded on your watch are uploaded to Intervals.icu automatically, so a run or ride tracked on your Fitbit or Pixel counts toward your training load without a manual export.
The coaching engine is the same, the wearable is yours to choose
All of this feeds the exact same readiness pipeline we've used from day one: personal baselines, multi-day trend detection, fatigue signals, training adaptations. Whether your overnight HRV comes from a Whoop strap, an Apple Watch or a Pixel Watch, the detectors, the baselines and the adaptations are identical. The coaching is ours; the device is yours.
That source-agnostic design also means you can mix devices. IntervalCoach merges everything into a single daily wellness record per athlete rather than letting sources fight over the same metric. Each field follows a clear priority, so if you wear a Whoop and a Pixel Watch, you won't end up with drift between sources or the app confused about which HRV reading is real. Add or drop a device whenever you like: the coaching picture adjusts without losing your history.
Your Intervals.icu dashboard stays in sync. Everything Google Health provides that Intervals.icu can store (HRV, resting HR, sleep, SpO₂, respiration, body weight) is mirrored there automatically, so your training platform stays the single source of truth for your history.
What shows up in coaching
The new data doesn't just sit in a log. It feeds the detectors that drive your readiness score and the Coach+ chat:
- HRV dropping below your personal baseline → elevates fatigue risk, may suggest a lighter day.
- Resting heart rate climbing against your baseline → an early sign you're not absorbing the load, often paired with a rough night's sleep.
- VO₂ Max declining against your 30-day peak → a sustained drop, together with chronic fatigue signals, is an early warning for burnout.
- Sleep score and sleep debt → your coach knows when you're running on a deficit and eases tomorrow's intensity accordingly.
If you want the full story behind these decisions, we've covered the coaching engine in depth: How IntervalCoach Adapts Your Workout Every Day walks through the morning pipeline that turns these signals into concrete workout changes, HRV-CV: What Volatility Tells You That HRV Alone Does Not explains why we care about HRV stability and not just today's number, and The Science Behind IntervalCoach documents the published research behind every threshold. Google Health simply widens the set of athletes that can feed this engine.
How it works in practice
Connect it once. Open Settings → Integrations, find Google Health, and connect your account. You'll see Google's standard permission screen; grant access to the data types you're comfortable sharing.
It syncs on its own. New sleep sessions, morning readings and workouts arrive automatically, so by the time you open IntervalCoach in the morning your dashboard already reflects last night.
Choose what to sync. Two toggles let you control it: sync your health data, sync your workouts, or both. Turn either off and that stream stops on the next cycle.
If you've been waiting for a way to get recovery-aware coaching from your Fitbit or Pixel without forcing another device into your setup, this is it. And if you already feed IntervalCoach through Intervals.icu, Apple Health or Whoop, nothing changes: Google Health just becomes another source the coaching engine can learn from.