What Is a Sleep Diary
A sleep diary is a written record you keep for 1-2 weeks (or longer) that documents your sleep and wake patterns, including bedtime, wake time, number of nighttime awakenings, time spent awake, nap duration, and daytime symptoms. It's one of the first tools sleep specialists request because it reveals patterns invisible in a single night.
Clinical Use in Sleep Medicine
Sleep diaries serve as the foundation for diagnosing and treating sleep disorders. Before a polysomnography test or home sleep apnea screening, your doctor uses the diary to understand your baseline. For insomnia, sleep diaries are essential to cognitive behavioral therapy for insomnia (CBT-I). The American Academy of Sleep Medicine recommends maintaining a diary for at least 2 weeks to establish reliable patterns because single nights vary too much to guide treatment.
The data points your doctor extracts from your diary include sleep latency (time to fall asleep), wake after sleep onset (WASO), total sleep time, and sleep efficiency. These metrics help determine whether you're dealing with insomnia, circadian rhythm disorders, or whether sleep apnea is fragmenting your sleep without you realizing it.
What to Record
- Timing: Bedtime, wake time, and actual sleep duration
- Nighttime events: Number of awakenings, how long you stayed awake, reasons if known (bathroom, noise, racing thoughts)
- Naps: Duration and time of day
- Sleep quality: Subjective rating on a scale (1-10 is standard)
- Daytime impact: Energy level, mood, focus problems, sleepiness at specific times
- Sleep hygiene factors: Caffeine intake timing, exercise, screen time before bed, alcohol use
- Medications: Sleep aids or other drugs taken
Common Questions
- How accurate does my diary need to be? You don't need exact times. If you estimate bedtime within 15 minutes or count awakenings approximately, that's sufficient. The goal is pattern recognition, not precision. Studies show people's estimates correlate well enough with objective measures for clinical decision-making.
- Should I keep a diary if I suspect sleep apnea? Yes. Your diary helps your doctor see how often you wake (even if you don't remember) and whether daytime fatigue matches the diary's sleep totals. This discrepancy often signals fragmented sleep from apnea events.
- Can I use my phone instead of paper? Either works. Apps designed for sleep tracking can be easier, but some people find that entering data manually forces better awareness of their patterns.