Headache diary: what to record, how long to keep it, and how to track migraine with your phone

Short answer

A headache diary is a day-by-day record of each headache: when it started, how long it lasted, how bad it was, what came with it and every medicine you took. NICE asks for at least 8 weeks of entries. Count medicine days too: acute medicine on 10 or more days a month (15 for simple painkillers) for more than 3 months is an ICHD-3 threshold.

Before you blame yourself, check what your body already recorded. If you cannot say how many headache days you had last month, that is not your fault — memory is bad at counting pain, and a diary is simply the tool that does it for you. A phone is enough to keep one, and if you want to add a physiological layer, you can try a guided migraine check-in in Welltory.

Note: this article explains how to keep and read a headache diary and is not medical advice. A diary supports a diagnosis made by a clinician; it does not replace one. If a headache is sudden and severe, comes with weakness, confusion, fever or a stiff neck, or follows a head injury, call 911 or go to an emergency department.

What is a headache diary, and why do doctors ask for one?

A headache diary — also called a migraine diary, migraine journal or headache log; they are the same thing — is a record you fill in as headaches happen, not afterwards. It exists because a migraine diagnosis rests almost entirely on the pattern of attacks. There is no blood test or scan that confirms migraine. The International Classification of Headache Disorders (ICHD-3), the diagnostic standard used worldwide, defines migraine without aura by what attacks look like over time: at least five attacks lasting 4 to 72 hours, with at least two of four features — one-sided pain, a pulsing quality, moderate or severe intensity, and pain made worse by (or making you avoid) routine activity such as walking or climbing stairs — plus nausea or vomiting, or sensitivity to both light and sound.

That is a lot to remember accurately, so the classification itself points clinicians to a diary. In its notes on chronic migraine, ICHD-3 says that characterizing frequently recurring headache "generally requires a headache diary to record information on pain and associated symptoms day-by-day for at least one month." For aura, it goes further: people often find aura hard to describe, get the side or the speed of onset wrong, and "use of an aura diary may clarify the diagnosis."

The UK's National Institute for Health and Care Excellence (NICE) guideline on headaches recommends considering a headache diary both to aid diagnosis and, later, to monitor whether a treatment is working. Its list of what to record is short and specific: frequency, duration and severity; associated symptoms; all prescribed and over-the-counter medicines taken for headache; possible precipitants; and the relationship to menstruation.

Why real-time entries matter. A classic study in the BMJ followed 80 adults with chronic pain for 21 days: 40 kept a paper diary with a hidden sensor recording when it was opened, and 40 kept an electronic diary. The paper-diary group reported filling it in on time 90% of the time; the sensor showed actual on-time compliance of 11%. On 32% of days the paper diary was never opened at all, yet entries existed for those days. The electronic diary reached 94% compliance. The lesson is not that people are careless. It is that remembering later, however sincerely, is a different thing from writing it down now.

What should you record in a migraine diary?

Less than you think, but the same things every time. Long forms tend to be dropped within weeks. Aim for something you can fill in within a minute on a bad day, with one hand, in a dark room.

A few practical rules make this work.

Write the aura down while it happens, or within the hour. ICHD-3 describes aura as fully reversible visual, sensory or speech symptoms, usually visual — often a zigzag shape near the centre of vision that slowly spreads. Its criteria use details most people do not notice unless they are looking: whether a symptom spread gradually over five minutes or more, whether symptoms came one after another, whether headache followed within 60 minutes. A voice note on your phone ("zigzag, left side, started 3:10, gone 3:35") is enough.

Log headache days that are not migraine too. A diary that only records the bad attacks cannot show a doctor the full count of headache days, and that total is what several diagnoses depend on. Chronic migraine, for example, is defined by headache on 15 or more days a month for more than 3 months, with migraine features on at least 8 of those days.

Keep notes short and literal. "Four hours' sleep, skipped lunch, long drive" is more useful later than "bad day." You are writing for a reader who was not there — your future self and your neurologist.

Record days without headache, briefly. A tick on a clear day proves the gap was real and not a missed entry.

Counting medicine days, and why it matters

Because it is the single field most likely to change what your doctor does next — and the one people underestimate most.

ICHD-3 describes medication-overuse headache as headache on 15 or more days a month in someone with a pre-existing headache disorder, developing as a consequence of regular overuse of acute headache medicine for more than 3 months. The thresholds depend on the class of medicine:

• 10 or more days a month for triptans, ergots, opioids or combination painkillers (for example, a painkiller combined with caffeine or codeine), or for several classes used together;

• 15 or more days a month for simple painkillers such as paracetamol (acetaminophen), aspirin or other NSAIDs.

ICHD-3 notes that these day counts are based on expert opinion rather than formal evidence. It also says that when someone is clearly overusing several medicines but cannot say which ones or how much, "in almost all cases" this needs diary follow-up. NICE uses the same 10- and 15-day thresholds and asks clinicians to be alert when headache developed or worsened while someone was using acute medicine on those days for 3 months or more.

This is common, and often invisible to the person. In the US CaMEO study, an internet survey of 16,789 people with migraine, 17.7% were using acute medicine at or above those day thresholds — and about two-thirds of them had fewer than 15 headache days a month, so they would not have met the full medication-overuse criteria. People using acute medicine that often carried a heavier disease burden and more emergency and urgent-care visits.

Count days, not doses. Two tablets on Tuesday is one medicine day. That is how the thresholds are written, and it is the number your doctor will want.

Do not change or stop a medicine because of what your diary shows. Which medicine, how often and whether to switch to prevention is your doctor's decision. The diary's job is to make that conversation specific. The ICHD-3 notes on chronic migraine add a hopeful point: medication overuse is the most common cause of symptoms that look like chronic migraine, and around half of people who appear to have chronic migraine return to an episodic pattern after the overused medicine is withdrawn under medical care.

How long should you keep a headache diary?

At least 8 weeks for diagnosis, per NICE. At least a month, day by day, before frequently recurring headache can be characterized, per ICHD-3. At least two or three menstrual cycles if the question is menstrual migraine: NICE suggests suspecting menstrual-related migraine when attacks occur mainly from 2 days before to 3 days after the start of bleeding in at least 2 of 3 consecutive cycles, and diagnosing it with a diary kept for at least 2 cycles.

After that, a diary changes job. NICE recommends considering a diary during management too — to monitor whether a treatment is working and as a basis for discussing the disorder and its impact. Preventive treatment is usually judged over months, so keeping at least a simple count of headache days and medicine days between appointments is what lets you and your clinician see whether something has changed.

Many people do not need to log in full detail forever. A pattern that works for a lot of people:

1. Weeks 1–8: full diary. Every field, every day. Change nothing on purpose; just record.

2. Before and after any treatment change: full diary again, for long enough to compare like with like.

3. In between: a minimal log — headache yes/no, severity, medicine yes/no. Ten seconds a day.

Expect gaps and keep going. A diary with a missed weekend is still far more useful than memory. Mark the gap plainly ("no record") rather than reconstructing it.

Triggers or prodrome: reading what you wrote

This is where a diary is most often misread — and it is worth slowing down.

Some "triggers" may be early symptoms of the attack itself. Many people have a prodrome, or premonitory phase: hours of symptoms such as tiredness, yawning, neck stiffness, food cravings or sensitivity to light before the headache starts. In a small but careful study, researchers at King's College London examined 53 people with migraine who had premonitory symptoms. Several of the triggers people reported lined up with their own premonitory symptoms: seeing bright light as a trigger matched premonitory light sensitivity, and blaming food or skipped meals matched premonitory food cravings. The authors concluded that at least some reported triggers, such as light, sound and certain foods, may be early brain manifestations of the attack rather than its cause. If you crave chocolate, eat it and then get a migraine, the chocolate may be innocent. Migraine prodrome vs trigger covers this in more depth.

How common is a prodrome? Less certain than it sounds. A 2022 systematic review and meta-analysis estimated that 29% of people with migraine in population-based studies, and 66% in clinic-based studies, reported at least one premonitory symptom — with very wide uncertainty and many low-quality studies. The authors concluded the evidence was not strong enough for reliable estimates.

For some people, a prodrome is consistent. In the screening period of the PRODROME trial, 920 adults who said they could recognise their own prodrome recorded symptoms in an electronic diary for 60 days. The most common were light sensitivity (57.2% of events), fatigue (50.1%) and neck pain (41.9%). Of the 4,802 prodrome events they logged, 81.5% were followed by a headache within 1 to 6 hours. Note who was studied: people selected because they were already confident they could recognise their prodrome, logging only moments when they felt sure a headache would follow. It does not mean everyone has one, or that every tired afternoon means an attack is on the way.

What this means for your diary:

• Log how you felt in the hours before an attack, as plainly as you log the attack. "Yawning a lot, stiff neck from about 11" is a line worth having.

• Treat "what came before" as a question for your doctor, not a verdict. A diary shows what happened near an attack; it cannot show what caused it.

• Look for repeats, not single coincidences. One migraine after red wine is an anecdote; five out of six is worth raising. Five out of six times that you also slept badly the night before is a different conversation again.

• Remember the stress story runs both ways. Some people get attacks during stressful weeks, others as the stress lifts. Stress and let-down migraine looks at what the evidence says about both.

Can you track migraine patterns with only your phone?

Yes, for the diary itself. A phone does everything a paper page does, and it does real-time entries better: it is in your pocket when the aura starts, it timestamps the entry, and it can take a voice note when reading a screen hurts. Electronic diaries also make it harder to back-fill a week from memory — which is exactly what the BMJ compliance study showed paper diaries invite.

What a phone alone cannot do is record your body continuously. It does not know how long you slept unless you tell it or connect a device, and it cannot record your heart rate through the day. It can, however, take a short spot reading with the camera: you place a fingertip over the camera and flash and hold still for a moment while the phone reads the pulse from tiny changes in colour. This method is called photoplethysmography (PPG). A spot reading is one snapshot of one moment. It needs you to be still, it cannot replace continuous heart-rate monitoring or an ECG, and it says nothing on its own about migraine. How accurate is HRV from a phone camera? goes through the validation evidence and its limits.

Here is how the main options compare.

None of these tells you when a migraine is coming. Research on wearables and migraine is active, but no consumer device is validated to tell you an attack is on its way, and neither is Welltory. Can a smartwatch predict a migraine? walks through what that research has and has not shown.

Reading a morning measurement next to your diary

If you add a physiological layer, keep it simple and keep it consistent. For the diary itself there are many good apps, and a paper page works too. If you also want a daily physiological line to sit beside what you wrote, a short morning reading adds that layer — with the phone camera if you have no wearable, or from a compatible watch or chest strap if you already have one. With a connected watch or ring, sleep and daytime stress can sit alongside it.

Take it the same way every day. Same time (shortly after waking works for most people), same position, same finger, before coffee and before checking messages. Do not press hard on the camera and do not move. A reading taken sitting up after a stressful email and one taken lying in bed are not comparable.

Write down how you feel before you look at the number. Energy, head, neck, mood — a word or a 0–10. Then look. This stops the number from rewriting how you feel.

Compare yourself with yourself. Heart rate variability varies enormously between people. What matters is your own range over a few weeks, not a population average or someone else's screenshot.

Read it in hindsight, not each morning in suspense. Once you have several attacks logged, go back and look at the readings, sleep and notes around each one, as context for what you wrote in the diary. Do not expect a build-up to show itself: in our own data the heart-rate difference sat in the day of the report itself and was already three to five times weaker a day later, so a visible run-up before an attack is not something to count on. Sometimes something repeats. Often nothing does, and that is a real answer too.

When the reading and your body disagree, believe your body. A good-looking number on a morning when your head feels wrong does not make the morning safe. The reading is one more line in the diary, not a verdict on how you should feel.

A diary is a record of what happened, not a judgement of you. The same goes for the number as for the log.

What our data shows about how people log migraines

We looked at people who write "migraine" in the Welltory app, because they show both what a diary is up against and what physiology can and cannot add. This is an internal, aggregated analysis of self-recorded labels. A label means someone typed the word, not that a clinician confirmed an attack, and its timestamp is the time of typing, not of onset. This is not a clinical sample: 90% of the cohort are women (migraine itself runs closer to 3:1), the median age is 46, and most people are in the US.

Most migraines appear never to get logged. Across 2,230 complete person-years (2019–2025) in which someone tagged at least one migraine, the median was 2 tagged attacks a year, and 48.7% of person-years held exactly one. People with episodic migraine commonly have attacks every month, so this is a large gap between logged and lived migraine — the same gap a diary exists to close. A single tag once a year cannot show a pattern to anyone. The same picture shows up over longer spans: 78.9% of everyone who has ever tagged a migraine appears in just one calendar year.

Heart rate barely moves, and not in a useful way. Across 1,615 people who had both migraine labels and enough measurements in 2023–2026 to compare their own labelled days with their own ordinary days, heart rate readings taken within 24 hours of a logged migraine were about 1 beat per minute lower than on the same person's days at least two weeks away from any migraine label, in about 60% of people. That is consistent across the group but far too small to identify a migraine day in any individual. The effect also points the opposite way to what you would expect: pain usually raises heart rate, and here it was lower, which we cannot explain. Most of it sat in the hours after the report rather than before. Nothing in this analysis detects or predicts migraine. HRV showed no reliable change once we corrected for heart rate, restricted to measurements the app flags as suitable, and accounted for which device took them.

People reach for the phone near a migraine report. Near a report, the share of readings taken with the phone camera rose from about 3.4% to 10.7%, while watch readings fell. This is a separate behaviour that does not explain the heart-rate difference, but it suggests the phone is what people have to hand at that moment — which is what a diary on your phone is for.

Migraine and "headache" labels looked the same in the body. They differed only in when and how people reported them. This null has a floor: the smallest difference the comparison could have detected was a Cliff's delta of 0.070, so a difference big enough to matter would have shown up, while a very small one could have gone unnoticed. That is one more reason the diary — what you felt, how long, what helped — carries the diagnosis, not the physiology.

The main limits: absence of a label is not absence of a migraine; timing is the timing of reporting; and no comparison with other kinds of labels has yet been run, so none of this is established as specific to migraine.

Diary app, wearable or both?

The diary is the part with evidence behind it as a clinical tool. Guidelines ask for it; the diagnostic criteria are written around it; treatment decisions are judged by its counts.

Extra app features have not yet been shown to do more than the diary itself. In a German randomized trial of 477 adults with migraine, a prescribable digital migraine app was compared with a version limited to basic headache-diary features over 12 weeks. Migraine days fell in both groups — from about 7.7 a month to 5.8 with the full app and 5.4 with the diary-only version — with no significant difference between them (0.38 days). Improvement in both arms of a trial is common for reasons unrelated to the app itself, so this does not show that a diary lowers attack frequency. What it does show is that a simple diary was not outperformed by a far more elaborate product.

Wearables add context, and the context runs both ways. A 12-week US study paired Fitbit data with daily headache surveys in people reporting 5–14 headache days a month; 350 had complete enough data for the main analysis. On headache days, people slept more, moved less and had a lower maximum heart rate. That is a picture of what a headache does to a day — lying down, cancelling the walk — more than a picture of what caused it. Worth remembering when a tracker shows "more sleep" next to an attack.

So use them together: the diary as the record your doctor reads, a morning reading or wearable for how your sleep and nervous system looked around attacks — both read in hindsight, and brought to the appointment as questions, not conclusions.

Living with migraine: the questions people ask next

Should I log a headache in my migraine diary if I'm not sure it was a migraine?

Yes — log every headache day in your headache diary and let the features decide the label later. ICHD-3 defines migraine by the pattern: attacks of 4 to 72 hours with features such as one-sided, throbbing, moderate-to-severe pain that worsens with activity, plus nausea or light and sound sensitivity. Tension-type headache, by contrast, is typically pressing and on both sides. Chronic migraine is counted across all headache days, including tension-type-like ones. If you only write down the "real" migraines, your neurologist sees a smaller, tidier picture than the one you live with. Write what you felt, not what you think it was called.

How do I keep a migraine diary at work without it taking over my day?

Keep the at-work part of your migraine diary to a timestamp and one line: "head started 2:15, left side, took medicine 2:30." Fill in the rest that evening. A phone note or voice memo is fast and discreet, and electronic entries keep their timestamps, which the BMJ diary study showed paper does not guarantee. If attacks affect your work, add one line of impact — "left early," "worked through it at half speed." NICE lists the impact of headache as part of the conversation a diary supports, and that line is the one that makes a clinician understand what the attacks cost you. For deciding about the next day, see going to work the day after a migraine.

What should I note about exercise, travel, heat or a missed meal in my headache diary?

Note them as plain facts in the "what came before" field of your headache diary: "long flight," "ran in the heat," "skipped lunch," "late night." NICE asks for "possible precipitants" in a diary, and that word — possible — is the right attitude. Research from King's College London found that some reported triggers, including skipped meals and food, lined up with people's own premonitory symptoms, so a craving or a skipped meal may be part of the attack rather than its cause. Record, then look for repeats over several months. If exercise brings on a headache, or a headache comes on with coughing, sneezing or straining, mention it to your doctor soon — NICE lists these as features that need a clinical assessment rather than a diary.

How do I track migraine around my period?

Add cycle day to your migraine diary, counting the first day of bleeding as day 1 and the day before as day −1; ICHD-3 notes there is no day 0. The appendix criteria for pure menstrual migraine describe attacks on days −2 to +3 in at least two of three cycles and at no other time; NICE suggests a diary covering at least two cycles to diagnose menstrual-related migraine. In a Dutch e-diary study of 500 women with migraine, perimenstrual attacks lasted longer than attacks at other times — a median of 20.0 versus 16.1 hours — and were more likely to recur after treatment. That is useful to know when you plan medicine with your doctor. Menstrual migraine covers hormones and treatment options in more depth.

Does sleep belong in a migraine diary?

Yes, briefly: roughly when you fell asleep, when you woke, and whether you woke with the headache. Sleep is one of the "possible precipitants" many people and clinicians look at, and ICHD-3 uses sleep in the definition itself — if you fall asleep during a migraine and wake without it, the attack counts until you woke. Be careful reading it backwards, though. In a 12-week Fitbit study of 350 people with frequent headache, headache days came with more sleep and less activity, which mostly reflects what an attack does to a day. A migraine diary that notes both the night before and the night of an attack lets you and your doctor tell those two stories apart.

How many painkiller days a month is too many for migraine?

ICHD-3 and NICE use the same thresholds for medication-overuse headache: acute medicine on 10 or more days a month for triptans, ergots, opioids or combination painkillers, or 15 or more days a month for simple painkillers such as paracetamol, aspirin or NSAIDs, for more than 3 months. ICHD-3 applies the diagnosis to someone with headache on 15 or more days a month. The thresholds count days, not tablets. In the CaMEO study, 17.7% of people with migraine used acute medicine that often, and most of them had fewer than 15 headache days. If your migraine diary shows you near these numbers, bring it to your doctor — do not stop or change a medicine on your own. Your doctor decides what to change.

Will I have to keep a headache diary forever?

Usually not in full detail. NICE advises at least 8 weeks of a headache diary for diagnosis, then suggests using one during management to see whether a treatment is working. Many people switch to a ten-second daily log — headache yes or no, severity, medicine yes or no — and return to the full diary for a few weeks before and after a treatment change. Migraine can change over time, and the diary is how you and your doctor see it. ICHD-3 notes that around half of people who appear to have chronic migraine revert to an episodic pattern after an overused medicine is withdrawn under medical care. A long-term log is how improvement becomes visible rather than just hoped for. Migraine treatment outlines the main treatment approaches.

Could my headaches be something worse than migraine?

Most recurring headaches are primary headaches such as migraine, but some features need a doctor quickly rather than a headache diary. NICE lists, among others: a sudden headache reaching full intensity within 5 minutes; a new neurological deficit such as weakness, numbness or difficulty speaking; new confusion or a change in personality; a worsening headache with fever; headache after a recent head injury; headache brought on by coughing, sneezing, straining or exercise; headache that changes with posture; and a substantial change in your usual pattern. The SNNOOP10 red-flag list adds headache starting in pregnancy or after childbirth and painkiller overuse. NICE also advises against brain scans solely for reassurance once migraine is diagnosed.

How to bring this up with your doctor

Start with primary care. If attacks are frequent, disabling or not responding to treatment, ask whether a neurologist or headache specialist would help. Either way, the diary is what makes the appointment work.

Seek emergency care, not an appointment, for: a sudden "worst headache of your life" that peaks within minutes; weakness, numbness, drooping of the face, confusion or trouble speaking; a headache with fever or a stiff neck; a headache after a head injury; or a new kind of headache starting after 50 — call 911 or go to an emergency department.

Bring a one-page summary, not the whole diary. Clinicians have minutes. Put the numbers at the top:

• headache days per month and migraine days per month, for each of the last two or three months;

• medicine days per month, by medicine;

• typical attack: duration, side, severity, what comes with it, whether aura precedes it;

• what you have tried, for how long, and what happened;

• impact: days missed or cut short at work, school or home.

Then bring the diary itself in case your doctor wants detail.

Open with one sentence. "I've kept a headache diary for nine weeks: 11 headache days a month, 6 with migraine features, and medicine on 9 days."

Ask specific questions. Does this pattern fit migraine, and which type? Am I near the medicine-day thresholds? Should we consider preventive treatment? What should I track differently before the next visit?

Mention what changes the picture: aura; attacks tied to your cycle; a recent change in pattern; new medicines, including hormonal contraception; poor sleep or snoring; and any headache features on the red-flag list above.

If you feel dismissed, say it plainly: "These headaches affect my work several days a month, and I'd like a plan for them." A diary makes that request much harder to wave away, because it turns "I get a lot of headaches" into numbers.

How Welltory helps — and what it cannot do

The limit first. Welltory is a general wellness product, not a medical device. It does not diagnose, predict, monitor, prevent, treat or mitigate migraine or any other condition, and it is not a substitute for your headache diary or your doctor.

For the attack diary itself, there are many good options. If you also want a daily physiological line to sit next to your entries, Welltory can add one with a short phone-camera reading — or from a compatible chest strap, Apple Watch or Samsung Watch. A routine that fits migraine:

1. Take one morning reading. Fingertip over the camera and flash, still, same finger, same time. The Heartbeat Report is designed for readings taken in the morning under the same conditions each day.

2. Log the attack and what came before. Add a tag for "migraine," "aura," "short night," "period day 1" or "long drive," or write a note any time: tap the plus icon and type in "Share your thoughts…". If you wear an Apple Watch or Oura on iOS, Welltory also flags stress stretches during the day and asks "What happened?" — you can tap a suggested tag, type a few words or just talk.

3. Look back over it in hindsight. Your morning HRV reading, resting heart rate, sleep, stress minutes and Battery as personal trends next to how you felt (stress minutes and Battery need iOS with a connected Apple Watch or Oura; Sleep Analysis currently needs an Apple Watch). When the number and your body disagree, believe your body.

4. My Patterns. On iOS with an Apple Watch or Oura feeding heart rate through the day, the tags you add to stress and rest episodes collect in My Patterns. After roughly two to three weeks of tagging — insights need at least 7 occurrences of a tag in the current month, plus some history from the month before — it shows which tagged situations show up most often in your stress episodes, tags that don't happen often but hit your body hard, day-of-week trends, heart rate during episodes and a complete list of every time a tag happened.

5. A log for your doctor or neurologist. Journal shows your HRV readings, tags, mood and how you feel physically, notes, workouts and menstrual cycles synced from Apple Health, Samsung Health or Health Connect. For an appointment, export a CSV from the web app (Dashboard → choose a chart → Export) and bring it with your headache diary. The free version keeps 30 days of data, so export before then if you want a longer record.

To start, try a guided migraine check-in in Welltory.

Patterns are associations to discuss with your doctor — not proof of a trigger and not a warning system. See migraine and your nervous system for what HRV can and cannot tell you, and My Patterns for how the feature works.

How we made it

Made with AI tools, then edited and fact-checked by the Welltory team. See our Editorial & AI policy.

Data analysis by Jane Smorodnikova, co-founder of Welltory and the person who built the methodology behind how we read physiological data.

Written by Tatsiana Yashyna.

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