At IFA 2025, Withings quietly leaned into a trend that’s become wearables’ new favorite buzzword: predictive AI. The company announced HealthSense 4, a firmware and OS refresh for the ScanWatch 2 that packs new algorithms across roughly 35 health metrics and, importantly, pushes alerts that try to flag health changes before you feel them — everything from signs you might be getting sick to nudges about an upcoming menstrual cycle. It’s an incremental product update dressed up as a leap forward: same hybrid-watch look, more health math under the hood.

What’s actually new

The headline changes are straightforward. HealthSense 4 updates the ScanWatch 2’s sensing and analysis: better step- and activity-tracking, a more detailed sleep-stage breakdown (including REM and clearer breathing / respiratory rhythm signals), and a suite of algorithms that tap temperature, heart-rate variability, SpO₂ and movement to make higher-level inferences about energy and fatigue. Withings says the update covers 35 metrics in total — a broader biometric net than before. On the hardware/UX side the company is also offering two new colors (blue and silver), but only for the 42mm model, and it claims battery life has nudged up to 35 days on a charge — roughly five days longer than the original ScanWatch 2.

For paying subscribers, Withings is adding a new Vitality Indicator inside Withings Plus. The idea is simple: roll up heart-rate variability, activity, nocturnal temperature, SpO₂ and other measures into a single “energy / fatigue” estimate so users can see at a glance whether they’re primed or running on fumes. Withings is also bundling a one-month Withings Plus trial with new purchases, which unlocks the AI assistant, the Vitality score and Cardio Check-Up — a paid service that routes ECG and heart data for cardiologist review.

The predictive part — how bold should you be about it?

The predictive alerts are the meat of the announcement and the part that will grab headlines: the watch will notify you if it detects patterns that often precede illness (small but persistent temp and HRV shifts, say) or changes consistent with the onset of a menstrual phase. That type of early-warning capability isn’t unique to Withings — Oura launched Symptom Radar last year with the exact same pitch: watch biometric deviations over time and flag potential early signs of respiratory illness or systemic strain. What’s notable is not that Withings built an illness-prediction tool, but that a company more associated with “hybrid watches that are quietly smart” is leaning into the same AI-wellness playbook as ring- and band-makers.

A word of healthy skepticism: these algorithms detect patterns and deviations from a personal baseline. They’re not diagnostic tools, and small sample-size signals (a poor night’s sleep, a late night, alcohol) can look like early illness. The broader industry has learned this the hard way — from pandemic-era experiments to recent regulatory tussles over when a wellness feature crosses the line into medical territory — so users should treat predictive alerts as prompts to pay attention, not prescriptions for action.

Withings has always tried to sit at the intersection of consumer design and clinical credibility. Its ScanWatch line previously cleared certain medical hurdles — Withings won FDA 510(k) clearance for earlier ScanWatch functionality back in 2021 — and that history helps the company claim a bit more legitimacy for health-adjacent features than a typical fitness brand might. But clinical credibility also creates expectations: people will ask how accurate the predictions are, how the models were trained, and whether the company validated them in real-world cohorts. Withings’ history of seeking regulatory review (and dealing with the practical chores that come with it, including software recalls and updates) means it’s used to that scrutiny — but it doesn’t remove the need for cautious interpretation.

Withings says the HealthSense 4 update will roll out to ScanWatch 2 owners starting in September 2025. The blue and silver 42mm versions go on sale immediately with a bundled one-month Withings Plus trial, and the watches start at $369.95 (Withings’ international pricing puts it around €349.95 in some markets). In short, it’s not a new physical product so much as a meaningful software refresh and a new positioning of the ScanWatch 2 as a more actively predictive wearable.

If you like the ScanWatch 2’s mix of classic watch design and medical-minded sensors, HealthSense 4 is a tidy evolution: deeper analytics, better sleep tracking, longer battery life and subscription features that try to make sense of messy human physiology. If you’re the kind of person who wants your devices to “tell you what’s coming” — and to do it with a level of clinical rigor — you’ll want to read the fine print: how Withings defines “predictive,” what data it uses, and how often those alerts actually translate into useful forewarning versus false alarms.

For everyone else, the update is another sign that wearable makers are increasingly comfortable offering probabilistic health nudges. The technology is getting better, but so are the expectations and the regulatory questions — and that tension is going to make headlines well after the new watch colors sell out.