How to keep a sleep diary

A sleep diary is a short morning note: when you went to bed, when you woke, and how the day started. Kept for a couple of weeks, it shows a pattern that one bad night hides. It is a record. It is not a diagnosis, and it is not a treatment.

Write it in the morning

The morning is when you still know the night. Do it before the day fills in. One entry is enough. Title it with the date, or tag it #sleep, in the same diary you use for everything else.

Four lines cover it:

• What time you went to bed, and what time you think you fell asleep.
• How often you woke, if you did, and what woke you. A guess is fine.
• What time you got up.
• How you felt in the first hour: rested, heavy, short-tempered, fine.

If you want a fifth line, note the obvious things that often sit next to a bad night: a late meal, coffee after dinner, a nap, a screen in bed, a worry you took to bed with you. Write them as facts. Do not turn the entry into a case against yourself.

Read a week, not one night

One short night does not mean much. A week of notes does. You might see that Sunday is the late night, or that you feel worse after eight hours in a hot room than after six hours with the window open. You might see that the nights you dreaded were ordinary. The point of writing it down is to replace the story "I never sleep" with the actual week.

If sleep is already a medical problem, this kind of note is something you can take to a doctor. It does not tell you what is wrong, and it does not replace asking someone who can. Do not use it to invent a regimen, cut sleep on purpose, or decide you have a disorder because three nights were bad.

Keep the nights private

Sleep entries are dull to everyone except you, and they still contain the shape of your life: when you are home, who shares the room, what you are afraid of at 2 a.m. Leave the diary private. The setting is explained in how to keep a private diary.

Friday morning. Bed at 12:30, asleep closer to 1. Woke once around 4, no reason I could find, back to sleep. Up at 7:10. Heavy until I had been outside. Coffee was late yesterday, around 4 p.m. That might be the 1 a.m. Not sure. Writing it so I can check next week.

If the morning note turns into the rest of the day, let it. A sleep diary can be the first line of an ordinary entry. More of those are in diary entry examples.