Apple's AI Health Coach Is Coming — Just Not Yet
watchOS 27 promises sharper heart-rate intelligence, but Project Mulberry's grand debut is slipping past launch day.
Written by OutOfToken AI
May 31, 2026 · 4 min read · Synthesized from reporting by 9to5Mac · How this works
Apple has spent years positioning the Watch as the definitive health wearable, and watchOS 27 is set to push that ambition forward — at least on paper. Bloomberg's Mark Gurman reports that heart-rate tracking is getting a meaningful hardware-and-software overhaul this cycle, while Project Mulberry, Apple's long-rumored AI health coach, is being held back from the initial release. The message from Cupertino is clear: ship what works, polish what doesn't.
Heart Rate Gets a Serious Upgrade
The headline technical improvement in watchOS 27 centers on heart-rate monitoring accuracy and granularity. Apple is reportedly refining the sensor algorithms that govern continuous tracking, addressing long-standing complaints about gaps in measurement during high-intensity workouts and irregular rhythms that fall below atrial fibrillation thresholds but still warrant clinical attention. The changes are expected to reduce latency in heart-rate reporting and improve consistency across skin tones and wrist positions — two areas where optical sensors have historically struggled. For users already relying on Apple Watch for cardiovascular monitoring, this is a foundational upgrade rather than a flashy feature.
Project Mulberry: Scaled Back, Not Scrapped
Project Mulberry has had a turbulent development arc. First surfaced in reporting from early 2025, the initiative describes an AI-driven health coaching layer capable of synthesizing Watch data — sleep, activity, heart metrics, nutrition trends — into personalized guidance. By February of the following year, reports indicated Apple had pulled back the scope of the project, raising questions about whether it would ship at all. Gurman's latest reporting offers a more optimistic read: Mulberry's core features are still targeting iOS 27 and watchOS 27, but they are unlikely to be present at launch. Instead, Apple appears to be planning a mid-cycle rollout, similar to how it has staged AI features in recent software generations.
"Apple is treating Project Mulberry the way it treated Apple Intelligence — announce the vision, ship the foundation, deliver the ambition in waves."
Why the Delay Actually Makes Sense
Health AI is a category where overpromising carries real-world consequences. Competitors including Whoop and Google's Fitbit have faced criticism for coaching features that feel generic or, worse, medically misleading. Apple's legal and regulatory caution is well-documented, and an AI that interprets heart data and dispenses wellness advice sits squarely in territory the FDA has begun scrutinizing. A staged rollout lets Apple gather real-world telemetry from the improved heart-rate hardware first, grounding Mulberry's recommendations in a more reliable data foundation before it makes clinical-adjacent suggestions to millions of users. That sequencing is deliberate, not a failure.
When Apple does ship Project Mulberry in full, it will land on top of a Watch platform with meaningfully better physiological sensing underneath it — and that combination could finally make the AI health coach story credible rather than aspirational. WWDC will reveal how much Apple is willing to commit to on stage; the real test comes when the software ships, whenever that turns out to be.
Editorial Note
The headline references 'watchOS 27' and 'iOS 27,' which do not exist as of the knowledge cutoff date (April 2024). Apple's current versions are watchOS 10 and iOS 18. While 9to5Mac is a reputable Apple news source and Mark Gurman is a credible reporter, this article either contains significant version number errors or is from a speculative future date that cannot be verified. Project Mulberry details and Bloomberg reporting may be accurate, but the OS version numbers make the core claims impossible to confirm.
Claim Tracker
AI-assessed
Attributed to Bloomberg's Mark Gurman but not independently confirmed in this article
Based on Mark Gurman reporting; release timing is speculative
Attributed to Bloomberg but not independently verified; specific technical details unconfirmed
This is a well-documented technical issue in wearable sensor research
This has been a documented user complaint and technical limitation
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