Guides
Tracking migraines with Apple Health
Your iPhone already keeps a health ledger — sleep, cycles, workouts, and yes, headaches. Used well, Apple Health turns a migraine diary from an isolated list of bad days into a record that sits alongside the rest of your body's data.
What Apple Health actually stores about headaches
Since iOS 13.6, the Health app has included a symptoms category, and headache is one of its entries. Each headache record carries a time range and a severity — present, mild, moderate, or severe — and lives in the same encrypted store as your steps and sleep. Any app you authorize can read or write these entries through HealthKit, Apple's on-device framework for health data. That's the quietly important part: Health isn't just an app, it's a shared, permission-controlled database that different tools can cooperate around.
What Health does not do is behave like a migraine diary. Logging a headache there means opening the app, browsing to Symptoms, and filling a form — nobody's idea of a mid-attack workflow. It records no attack context (no weather, no pressure, no triggers, no medication response), and it won't count your headache days per month or draw a pattern out of them. Think of it as the filing cabinet, not the clinician's assistant.
Why two-way sync beats a walled garden
Plenty of trackers treat your entries as theirs: data goes in, and gets out only as a screenshot. A diary that syncs with HealthKit in both directions behaves differently. Attacks you log in the diary are written to Apple Health as proper headache records, where they join your permanent health history. And headache entries that originate elsewhere — typed into the Health app directly, or logged years ago in another tracker that also wrote to HealthKit — flow into the diary, so your history is complete in one view.
The practical wins are bigger than they sound. Your record outlives any single app: switch tools in three years and your headache history comes with you. Nothing gets siloed: a partner app, a clinician-recommended tool, and the Health app itself all see the same truth. Dim syncs two-way from the start — an attack logged in three taps lands in Apple Health automatically, and your pre-Dim headache entries show up in Dim without retyping a single one.
HealthKit permissions are granular and revocable. You decide, per data type, what an app may read and what it may write — allow sleep reading but deny cycle data, for instance — and you can change your mind any time in Settings. An app never sees more than you granted.
Sleep: the context you get for free
Of all the data already sitting in Apple Health, sleep is the most valuable to a migraine diary. Sleep disruption is among the most commonly reported attack triggers — the American Migraine Foundation notes the link runs in both directions, with short nights and oversleeping both implicated — and if you wear an Apple Watch or use a sleep-tracking app, months of nightly data are already recorded, involving zero extra effort from you. The missing step is connection: your sleep numbers live in one place and your attack log in another, and nobody cross-references them at 6 a.m. with a building headache.
A synced diary closes that gap mechanically. When you log an attack in Dim, it reads last night's sleep from Apple Health and attaches it to the entry alongside the local weather, temperature and barometric pressure it captures on its own. Over a few months you get the comparison that actually answers the question — attack-night sleep versus ordinary-night sleep — rather than a vague sense that you "sleep badly before migraines." Our sleep and migraine page digs into what the research suggests about that relationship.
Privacy: what on-device exchange means
Health data deserves plain answers, so here they are. The HealthKit exchange happens entirely on your iPhone — when Dim reads a sleep record or writes a headache entry, that's a conversation between the app and the encrypted Health store on the device, not a round-trip to anyone's server. Apple's own protections apply on top: Health data is encrypted on the phone, and with two-factor authentication enabled it is end-to-end encrypted in iCloud — meaning not even Apple can read it.
Dim adds a simpler guarantee: there is nowhere for your data to go. The app has no account system, no ads, no analytics brokers, and nothing is sold; your diary lives on your device and in your own private iCloud, and leaves only when you choose to export it — say, as a PDF report for your neurologist. A migraine history is a medical record. It should move only when you move it.
Quick answers
Do I need an Apple Watch for any of this?
No. HealthKit sync works iPhone-only. A Watch adds automatic sleep tracking and wrist logging, but the two-way headache sync and context capture work without one.
Will my old headache entries from another app appear in Dim?
If that app wrote them to Apple Health, yes — grant Dim read access to headache data and your existing entries appear in the diary alongside new ones.
Can I revoke Dim's Health access later?
Yes, at any time, per data type, in your iPhone's Settings under Health. Your diary keeps working; it simply stops exchanging the revoked data.
A diary that talks to your Health app
Dim syncs headaches with Apple Health both ways and pulls last night's sleep into every attack log — all on-device, no account.
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