Sleep Journal

Sleep tracking is one of the most evidence-backed behavioural interventions for improving sleep quality. Simply recording your sleep — even manually — activates metacognitive awareness that tends to motivate better habits. Cognitive-Behavioural Therapy for Insomnia (CBT-I), the gold-standard treatment for chronic insomnia, uses sleep diary data as the foundation for all adjustments to sleep schedules and stimulus control.

Unlike wearable devices, a manual journal captures nuanced information that sensors miss: what you ate or drank, stress levels, exercise timing, and subjective experiences like vivid dreams or mid-night anxiety. Over weeks, patterns emerge that explain persistent sleep problems in ways that raw duration data alone cannot.

Sleep efficiency is the percentage of time in bed that you actually spend asleep. It's calculated as: (time asleep ÷ time in bed) × 100. A healthy sleep efficiency is 85% or higher. Chronic insomniacs often show efficiencies below 70%, meaning they spend significant time in bed lying awake.

CBT-I uses a technique called sleep restriction therapy — temporarily limiting time in bed to match actual sleep time — to rapidly improve efficiency. As efficiency climbs above 85%, time in bed is gradually extended. This is one of the most effective insomnia treatments available, though it requires guidance to implement safely.