Sleep and migraine: which one is driving the other?

Sleep is one of the most consistently reported migraine triggers. It is also one of the most consistently reported consequences, which is what makes it hard to reason about.

The US National Institute of Neurological Disorders and Stroke and the NHS both list disrupted or insufficient sleep among commonly reported migraine triggers. Notably, it is not only too little: a change in routine — including sleeping longer than usual on a rest day — is frequently described.

The direction problem

An attack disturbs sleep. Poor sleep is reported before attacks. Both can be true, and from inside one week it is close to impossible to tell which came first. Anticipating a bad night can itself make sleep worse, adding a third strand.

This is not a reason to give up on the question. It is a reason not to trust a conclusion drawn from a handful of remembered nights.

What a record separates that memory cannot

Two things help. First, sleep recorded at the time rather than reconstructed after an attack — recall of last week's sleep is heavily coloured by what happened since. Second, enough days that ordinary variation stops dominating.

Mira can read daily sleep summaries from Apple Health, read-only and optional, so the sleep side of the comparison does not depend on remembering. Attacks are timestamped when they start. That makes "did short sleep precede attacks more often than chance" a question about records rather than impressions.

Being honest about the answer

A pattern between your sleep and your attacks is an association in your own data. It is a good thing to raise with a clinician and a poor thing to treat as proof of cause — the same caution that applies to weather. Mira states how much data each pattern rests on for exactly this reason, and says nothing when there is not enough.

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This article describes general patterns from published clinical sources. It is not medical advice, diagnosis, or a treatment recommendation, and Mira is not a medical device. If your headaches are new, changing, or affecting your daily life, talk with a qualified clinician. This article — and Mira itself — exists to make that conversation more concrete, not to replace it.