Worked example
How a sleep window is set, step by step
This page follows Sam, a made-up person. It shows how the method turns a week of diary entries into a sleep window, and how that window moves week by week.
This is an example, not your window
There is nothing to fill in here and no personal answer. Spending less time in bed is not right for everyone. In the course, this step sits behind a safety check, and every change to your window is one you confirm yourself.
Step 1: a week of diary entries
Sam keeps a sleep diary for seven nights, writing down roughly when they went to bed, how long they lay awake and when they got up. Some nights are short and some are longer. A week shows a pattern that one night cannot.
Step 2: the starting window
The sleep window is the time Sam plans to spend in bed each night. It starts close to the amount of sleep Sam is getting, not the time Sam has been spending in bed.
Step 3: a fixed wake time
Sam picks one wake time to keep every day, weekends included. When the window changes, the bedtime moves and the wake time stays put.
Step 4: the weekly check
Each week, Sam looks back at the diary to see how much of the time in bed was spent asleep. The guide then suggests one of three things:
- Mostly solid nights
- The window grows a little.
- Mixed nights
- The window stays the same.
- Mostly broken nights
- The window shrinks a little.
The guide suggests. The person decides. Sources vary on the exact cut-offs, and the course explains the ones it uses after the safety check.
Sam, week by week
| Week | What the diary showed | What the guide suggests | What Sam does |
|---|---|---|---|
| 1 | Mostly solid nights | Grow the window a little | Confirms the change |
| 2 | Mixed nights | Keep it the same | Confirms the window |
| 3 | Mostly broken nights | Shrink the window a little | Confirms the change |
Step 5: the safety floor
However short the nights in the diary, the window never goes below a safety floor. Someone who is sleeping very little starts at the floor, not below it.
The floor also applies after the weekly check. If shrinking the window would take it under the floor, the window stays at the floor.
Before anyone tries this
Less time in bed can make you sleepier in the day for a while. Take care with driving and machinery. If you have a health condition, are pregnant, or your work is safety-critical, speak to a clinician first. We suggest you speak to a clinician if you are unsure.
In the course, the window is worked out from your own diary, after the safety check, and you confirm every change.
Educational, not a diagnosis.
If you are worried about your sleep, or you snore loudly, stop breathing at night or feel very sleepy in the day, we suggest you speak to a clinician.
Questions
Common questions
- What is a sleep window?
- A sleep window is the set time you spend in bed each night, from a bedtime to a fixed wake time. It starts close to the amount of sleep you are getting and is adjusted each week.
- Why is there a safety floor?
- Cutting time in bed too far can leave people very sleepy in the day. The window never goes below a set minimum, whatever the diary shows. The course explains its floor after the safety check.
- Can I use this page to set my own window?
- No. It is a fixed example to show how the idea fits together. In the course, this step comes after a safety check, and any change to your window is one you confirm.
- Why does the wake time stay fixed?
- Getting up at the same time every day keeps your body clock steady. The window moves by changing the bedtime, not the wake time.