What to log during a migraine episode — and what your doctor actually needs to know

Keeping a migraine diary is one of the most consistently recommended actions by neurologists and headache specialists — and one of the most inconsistently followed. Part of the problem is that most people are not sure what to log. Should it be just the headache? The whole day? Everything they ate?

This guide is practical. It covers what is worth recording, what doctors actually find useful, and how to make the process manageable even during a bad attack.

Why it matters — what the research actually says

A 2025 study at Ghent University Hospital compared smartphone-based headache diary data with clinical interview data in migraine patients over several months. The study found that daily diary tracking captured significantly more episode detail than retrospective clinical interviews, and that the two methods produced meaningfully different pictures of frequency and severity.¹ In other words: what patients reported at their appointment was often different from what they had actually experienced.

A 2023 review in the Journal of Neurology noted that "retrospective recall can over- or underestimate the contribution of a perceived trigger" and recommended that patients keep a headache diary specifically to identify individual triggers and trigger combinations.² The recommendation is not new, but it is consistent: structured daily recording produces more accurate data than memory.

What to log — in order of importance

Episode start and end time

Duration is one of the most clinically useful metrics in migraine management. A migraine that consistently lasts four to six hours responds differently to treatment than one lasting eighteen hours or more. Log when it started and when it fully resolved — a good tracker calculates duration automatically.

Severity at peak

Use a 0–10 scale consistently. The key word is consistently — if 8 means "unable to work or function" on day one, it should mean the same on day ninety. Inconsistent scoring reduces the value of your data over time.

Aura

If you experience aura, log the type: visual (zigzag lines, blind spots, flickering lights), sensory (tingling or numbness, usually starting in the fingers), speech (difficulty finding words), or motor (weakness on one side — less common). Aura type matters for diagnosis and affects which treatments are appropriate and safe.

All four phases

Migraine has four recognisable phases, and logging all of them — not just the headache — gives a much more complete picture:

• Prodrome — the hours or days before the headache: fatigue, food cravings, mood changes, neck stiffness, yawning.
• Aura — neurological symptoms that come before or during the headache.
• Attack — the headache itself, with associated symptoms.
• Postdrome — the aftermath: brain fog, exhaustion, low mood. This can last twenty-four to forty-eight hours and is often overlooked in records despite significantly affecting quality of life.

Associated symptoms

Nausea, vomiting, photophobia (light sensitivity), phonophobia (sound sensitivity), neck stiffness. These are part of the diagnostic criteria for migraine and help distinguish it from other headache types. Logging them also helps track whether they are improving or worsening over time.

Medication — timing matters

Log what you took, at what dose, and — critically — at what point in the attack. Timing matters enormously for certain treatments. Triptans, for example, are most effective when taken early in the attack, before the headache is fully established. If you consistently take medication late because you are hoping the attack will pass, that pattern is important for your neurologist to know. Also record whether the medication helped, partially helped, or made no difference.

Likely trigger

What do you think preceded this episode? Poor sleep the night before, a hormonal phase, a long screen session, a weather change, stress, alcohol, a skipped meal. Log even uncertain triggers — over time, the ones that consistently appear before attacks will separate from coincidence.

What neurologists are actually trying to establish

Understanding what your clinician needs from you helps you prioritise what to communicate. At a headache appointment, a neurologist is typically trying to answer:

• How many headache days per month? (This distinguishes episodic from chronic migraine.)
• How many days per month is medication being taken? (Overuse of acute medication — more than ten to fifteen days per month depending on type — can cause medication overuse headache, which worsens the underlying condition.)
• Is acute treatment working, and how quickly?
• Is frequency increasing, stable, or decreasing?
• What have you tried, and what happened?

A three-month diary typically provides enough data for a meaningful assessment. Six months allows seasonal and cyclical patterns to become visible — which is particularly useful for hormonal migraine or patterns linked to weather or work cycles.

Park et al. analysed diary data from 4,579 days logged by 62 migraine patients using a smartphone headache diary. The most common trigger factors recorded on headache days were stress (57.7%), sleep deprivation (55.1%), fatigue (48.5%), and hormonal changes — findings that aligned with the broader epidemiological literature but were captured at an individual level.³

What to do with the information

The migraine diary is not just a record — it is a working document. Review it before each appointment. Look for what appears most often before severe attacks. Note whether any treatment consistently helps or consistently does not. Come to the appointment with a summary, not a stack of entries.

A formatted report — one that shows episode frequency, average severity, top triggers, and medication use — is far more useful in a fifteen-minute consultation than trying to recall the last few months verbally.