Sleep Log
What It Measures
A sleep log is a daily record kept by the person themselves, usually for one to two weeks. Each morning they note what time they went to bed, roughly when they fell asleep, whether they woke in the night, and when they got up. Each evening they note caffeine, alcohol, medication, exercise, naps, and how sleepy they felt during the day.
Two weeks of that produces something no questionnaire can: the actual pattern. Recall is unreliable for sleep, and a person who reports sleeping badly may turn out to be sleeping seven hours on a shifted schedule, or napping at four in the afternoon. The pattern is what a clinician works from.
Additional Notes
Licensing Notes: A sleep log or diary is a method, not a proprietary instrument, and no license applies. The version this row links to is published by the National Heart, Lung, and Blood Institute, a US federal agency, and is in the public domain. Many other free versions exist, including the American Academy of Sleep Medicine's two-week grid format.
Learn More: One instruction changes the quality of the data more than any other: do not clock-watch. Repeatedly checking the time worsens both the sleep and the record. The convention is to turn the clock away and estimate in the morning, which is how clinicians read a diary anyway. Sleep logs are often paired with actigraphy, and are the standard tool in circadian rhythm sleep disorders and in CBT for insomnia.
