Keep a symptom diary: what belongs in it, when paper is enough and what an app adds

A symptom diary turns memory into numbers: each day you write down which complaint you had, how strong it was and how long it lasted. You can keep it on paper, in a notes app, or in Sam, where one tap records the day in the symptom diary and your symptom days and top symptoms come together in the monthly report instead of staying in a loose sheet. This post says what belongs in it and when paper is enough.

What a symptom diary is

A symptom diary is a list where you record day by day which complaint you had, how strong it was and how long it lasted. A sheet of paper works, as long as you really keep it. An app is worth it when you want to count days and look back over months.

The purpose is simple: your practice gets numbers instead of memory. To the question "Since when and how often?" you answer with days instead of a feeling.

Professional texts rely on this too. The headache classification ICHD-3 states that frequently recurring headache generally requires a diary, kept day by day for at least one month. The Migraine Trust says a diary can help your doctor make a diagnosis, help you see triggers, show whether your medicine works, and reveal patterns to your attacks.

What belongs in a symptom diary

These eight details are a solid base. Keep it simple, one line per day is usually easier to keep up than a long form.

• Date: every day counts, including the good ones. An empty field later reads as "forgot" or "all fine", and nobody can tell which it was.
• Complaint: in your own words, for example "left knee" or "pressure behind the forehead".
• Strength: three levels are enough, mild, moderate or strong. Some diaries use a scale of 0 to 3.
• Duration: an estimate is fine, an hour, until noon, all day.
• Time: only if it matters, such as at night or right after waking up.
• What you did or took: write what it was, and for medicine use the name from the packet.
• Sleep: a keyword is enough, good, poor or short.
• Special notes: an infection, stress, a trip, a new medicine, plus a short note.

An example line (invented): "Thu, left knee, moderate, about three hours, after gardening, slept well." More than that you do not need to start.

Paper, notes app or diary app

All three work. They differ in how fast you enter and how easily you count later.

An app is not automatically more reliable. Paper has a known weakness, though: entries get collected later instead of written at the moment.

What the paper-diary study really shows

In 2002 the BMJ published a study of 80 adults with chronic pain. Of these, 40 kept a paper diary and 40 kept an electronic diary. The paper diary booklet was fitted with a light sensor that recorded when it was opened, without the patients being told.

The people using paper reported filling in 90 percent of the entry times. The sensor showed the real figure was 11 percent within the 30-minute window, or 20 percent with a wider one. On 32 percent of days the booklet was never opened, yet participants reported filling those days in. The electronic diary in the same study reached 94 percent, with a reminder sound and entries locked outside the set windows.

Read this with context. The study is from 2002, it demanded three fixed entry times a day, and several authors had ties to an electronic diary provider. For your own diary it is a hint, not proof. Still, enter on the same day, ideally in the evening as a fixed habit. Adding later is better than leaving a gap. The longer you wait, the more you guess. Mark backfilled days briefly as "added later", so your practice knows what is an estimate.

Ready-made templates from UK patient groups

Therapists and patient groups publish diaries we link rather than copying:

• The Migraine Trust headache diary is a monthly template as a PDF or Word file, for recording attacks, severity, symptoms and medicine.
• The British Heart Foundation offers a blood pressure chart and diary, a 25-week diary for readings at home.

If none fit, build your own: one sheet, the details from above as columns, one line per day.

How to take the diary to the appointment

Take one page, not the whole notebook. Ask the practice first which period it wants to see. At the top of the page write three things: the time range, on how many days you entered, and on how many of those the complaint was present.

Example with invented numbers: "Range 12 Oct to 8 Nov, entered on 28 days. Left knee on 12 days, on 3 of them strong. On 16 days no complaints."

Then it is clear at a glance how many days sit behind a number. Bring the original entries as well. For the rest of the visit, the doctor appointment checklist for a chronic condition helps you prepare.

What a symptom diary cannot do

It shows when something happened. It does not say what it means. That is for the practice. If two things happen on the same day, that is not proof that one caused the other. If you notice something when you read back, that is a question for your doctor, not an answer.

A diary with gaps shows only the days you entered. A blank page does not mean nothing happened.

It also does not replace a call to the practice. A diary is not for emergencies: if you are seriously unwell, call your local emergency number (999 in the UK, 911 in the US, 112 in the EU). Symptoms that are new, severe or getting worse quickly should be checked by a doctor first, not just written down.

When the general diary is enough, and when there is a program

The general symptom diary fits when you are recording complaints for a work-up, or when you have several complaints at once. Once your practice has diagnosed a condition, a diary built for that condition can help more. Migraine counts attacks, epilepsy counts seizures, asthma counts attacks and reliever use.

For making the most of what you record, see what belongs in a report for the doctor and, for people tracking several conditions, managing multiple conditions and keeping records. Deciding whether a tool is right is covered in what a health app can and cannot do.

Keep symptoms in Sam and take a monthly report to the appointment

At month end you hold days instead of a feeling.

• Against paper or a notes app: you pick your symptoms in Sam from a catalogue, instead of wording them differently each week.
• Against Apple Health alone: the monthly report adds sleep and activity to your symptom days; you enter only what you know yourself.
• Against a page from a notebook: the monthly report shows symptom days on a calendar and your most common symptoms, shareable as a PDF.
• Against trusting memory: one tap records a symptom day, and a sick day can carry an optional test photo or doctor's note.

The symptom diary you keep without a doctor's diagnosis, and it has no report of its own. For eight conditions there is also a program with its own doctor report once a doctor has diagnosed the condition.

Try Sam for free

Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any condition or health state. Always consult qualified professionals for medical decisions.

Related reading

• What belongs in a report for the doctor
• Managing multiple conditions and keeping records
• Doctor appointment checklist for a chronic condition
• Your own health record vs a health app

Sources

Updated: October 2026

• International Headache Society: ICHD-3, 1.3 Chronic migraine
• Stone AA, et al: Patient non-compliance with paper diaries. BMJ 2002;324:1193
• The Migraine Trust: Keeping a headache diary
• British Heart Foundation: Your blood pressure chart and diary