Q&A: Start Sleep Restriction Right for Best Results

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Recently I’ve heard from a handful of people starting out with sleep restriction therapy (SRT), a treatment for insomnia. All were in a similar predicament. Here’s what Jenny wrote:

‘I’m on Day 4 of SRT and it isn’t going well. I finally had an appointment with a sleep therapist last week. He talked to me about SRT and gave me a 7-hour sleep window, from 11 p.m. to 6 a.m. My usual bedtime is 9:30 so I had some apprehensions. But I started 4 days ago.

Since then I haven’t slept more than 3 hours a night. It’s really hard for me to stay up till 11, and then when I get in bed I’m wide awake! In the morning I’m so tired I can hardly keep my eyes open! Is this normal? I’m afraid I may be a treatment failure. Any advice?’


The first few weeks of SRT are not much fun. Your time in bed is cut short at night and naps are not allowed. It can be hard to figure out what to do during the extra hours you’re up. In the daytime you may feel sleep deprived: exhausted, cranky, off your game.

Is this normal?

Research suggests it’s not abnormal. Results of a study of 16 insomniacs in the UK showed that while their sleep was greatly improved following SRT, during the first few weeks of treatment, they were sleep deprived. Like Jane Fonda said: no pain, no gain!


Jenny’s experience of the first few days of SRT is not so unusual. But nowhere in her email—or in the others I received—was there any mention of having kept a sleep diary* during the week before treatment. Also, all 4 I heard from were starting SRT with rather generous sleep windows: 6.5, 7, and even 8 hours in bed. Yet they didn’t say how those sleep windows were established.

Maybe sleep diaries were kept—and the writers just didn’t mention them. Or maybe a therapist determined, based on a clinical interview, that starting out with a generous sleep window was the best way to treat insomnia in that particular person. (See my blog on paradoxical insomnia for more on this.)

But I suspect that at least some who wrote had plunged right in to sleep restriction without filling out a sleep diary the week before and that their sleep windows were set arbitrarily. This can make the first week of sleep restriction even rockier than it needs to be—and might lead people to think the treatment is failing and quit.


To set your sleep window (time allowed in bed) at the start of SRT, you need to know how much sleep you’re getting from night to night. Maybe you have a pretty good idea of that already. In reality, though, most insomnia sufferers are not very good at estimating sleep duration.

Keeping a sleep diary during the week before treatment won’t necessarily make your estimate more accurate—but it might. By noting in the diary how many times you wake up each night, how long the wake-ups last, and the variability in your sleep from night to night, you might get a more realistic read on the average number of hours you sleep.


Regardless of whether keeping the diary clues you in to anything you didn’t already know, the results are an indication of how much your time in bed should be restricted at the start of sleep restriction:

  • You discover you’re a 6-hour sleeper? Start SRT with a 6-hour sleep window.
  • You’re sleeping 5 hours 15 minutes a night? Start with a 5.25-hour sleep window.
  • There’s one exception: most sleep experts (but not all) recommend starting SRT with nothing less than a 5-hour sleep window. So 4-hour sleepers are usually advised to start with a 5-hour window.

If you start with a too-small sleep window, you’ll wind up very sleep deprived. But if your sleep window is too generous (as I suspect may have been the case for Jenny and the others who wrote in), you’re likely to continue with the same broken sleep pattern you’ve known from before. This could sour you on sleep restriction even before you’re off the ground.

So keep a sleep diary for a week before starting SRT and set your sleep window accordingly. It’s the quickest path to success.

* Download this sleep diary from the National Sleep Foundation and make several copies for use during SRT.

What was your experience like during the first week of sleep restriction therapy?