On-device AI health coaches and Apple Intelligence
Short answer: An on-device AI health coach uses a language model that runs on your iPhone, such as Apple's Foundation Models with Apple Intelligence, to answer questions about your data without sending it anywhere. It needs an Apple Intelligence-capable iPhone (iPhone 15 Pro or later). It's private and has no usage caps, but it's a smaller model than cloud chatbots, so good apps keep its answers short and grounded in your numbers.
Cloud AI vs on-device AI
| Cloud AI coach | On-device AI coach | |
|---|---|---|
| Where your data goes | To the provider’s servers | Nowhere |
| Cost per question | Real, so often capped | None, so no caps |
| Works offline | No | Yes |
| Model size | Very large | Compact (~3B parameters) |
| Best at | Long, open-ended chat | Short answers grounded in your data |
How Apple Intelligence makes it possible
Apple’s Foundation Models framework gives apps access to the language model that powers Apple Intelligence, running on the iPhone’s Neural Engine. Apps send it a prompt and get text back, without a server.
What a good on-device coach does
- Grounds every answer in your numbers: recovery, HRV, sleep and habit impacts, summarised compactly
- Keeps answers short and specific: one action, one reason
- Never contradicts the scores: the training call comes from the score, not the model
- Falls back gracefully: a rule-based coach on iPhones without Apple Intelligence
- Avoids diagnoses: points you to a doctor instead
Pulse Coach’s coach
Pulse Coach writes a daily briefing and answers questions like “What’s my biggest recovery lever?” entirely on your iPhone. Pro includes unlimited questions, with no weekly credits, because each answer costs nothing to run.
Questions people also ask
Which iPhones can run an on-device AI coach?
iPhones that support Apple Intelligence (iPhone 15 Pro, iPhone 15 Pro Max and later) with Apple Intelligence turned on in Settings and its model downloaded.
Does an on-device coach work offline?
Yes. The model runs locally, so answers don't need an internet connection.
Can an AI coach give medical advice?
A responsible one won't. Pulse Coach's coach is instructed never to diagnose, and it suggests seeing a doctor when something looks unusual.
Sources
Not medical advice. This article is general information about wellness metrics. It is not a diagnosis or a substitute for professional care. If a reading worries you, or you feel unwell, talk to a doctor.