What is sleep restriction therapy and how it does it work?
Sleep restriction therapy is an evidence-based treatment of chronic insomnia. It was developed by Glovinsky and colleagues (1991) and is one of the most effective treatments for people who are experiencing sleep disturbances.
Sleep restriction therapy works by limiting the amount of time people spend in bed awake. The idea is that people with insomnia often spend a lot of time in bed awake because they are afraid of not getting enough of sleep and how this lack of sleep might affect their daily life or their health. Because of this, people with insomnia give themselves ample sleep opportunity by going to bed earlier, sleeping in, and staying in bed when they are not sleepy.
Although these behaviours make a lot of sense, this actually counterproductively affects sleep quality. This is because sleep gets stretched out very thin because the amount of sleep the person is producing is not matching well to the amount of hours they are spending in bed.
This results in two big problems.
First, excessive time in bed diffuses our homeostatic pressure for sleep. Because we don’t build up the necessary pressure for deep sleep, the sleep we end up getting is a lot lighter and less refreshing. For more information on how spending too much time in bed can lead to insomnia, see this post here on the 8-hour sleep myth!
Second, the time spent in bed awake (and likely in distress because we are not sleeping) can lead to conditioned arousal. This is when our bed becomes associated with wakefulness, rather than sleep.
Therefore, sleep restriction therapy works to consolidate our sleep by reducing time awake in the middle of the night. This is done by looking at a person’s sleep diary data (see this website for information on the sleep diary) and matching the time in bed closer to how much sleep is being produced.
The effect of sleep restriction therapy is increased quality of sleep over time. Moreover, because sleep restriction puts greater pressure on our sleep, we begin to spend more of our time in bed sleeping, which tackles some of the conditioned arousal that has been built up.
But I’m worried that sleep restriction therapy might lead to me getting less sleep…
This worry is very common among people with insomnia that I have worked with as a clinician. People are often worried that they are only getting so many hours in the first place and limiting opportunity to sleep may reduce the amount of sleep they get even more. This is a scary thought.
Fortunately, this isn’t what happens.
Research suggests that sleep restriction therapy does not reduce total sleep time (Riemann & Perlis, 2009), though there is a slight reduction in the early phases of treatment (Kyle et al., 2014). This is not surprising since the change in schedule requires some time to adjust to in the early stages of treatment.
Therefore, ‘sleep restriction therapy’ is kind of a misnomer. In reality, time-in-bed restriction therapy is a more accurate name for this treatment. It is a way to bring the amount of time you are spending in bed to the amount of sleep your body needs.
A graphical story of sleep restriction therapy
The above graphs are a theoretical example of changes in sleep duration and time in bed with and without sleep restriction therapy.
The left graph represents time spent asleep and the right graph represents time spent in bed. Blue is sleep restriction therapy and orange represents no sleep restriction.
In this example, you can see a slight decline in sleep duration after the first session with sleep restriction therapy because the body is adjusting. Some sleep deprivation in the first weeks beginning the treatment is common. What happens after is that our sleep drive kicks in and returns back to baseline within a couple weeks. There may even be an increase (as you see in session 4) because the person begins to feel more confident about their sleep and anxiety reduces. Anxiety can sometimes mask sleep because your body is in a fight-or-flight response, which is of course an enemy of sleep.
Although sleep time stays relatively similar in both groups, where things begin to differ is time in bed – which is depicted on the right side. Here, you notice a significant change in the amount of time a person is spending in bed throughout sleep restriction therapy. This is because sleep is being consolidated in sleep restriction therapy, which reduces awakenings and improves the quality of sleep.
Putting it all together
Sleep restriction therapy is an effective evidence-based treatment of chronic insomnia. Moreover, sleep restriction therapy increases the quality of sleep and reduces nighttime awakenings without significant impact on total sleep time.
Sleep restriction therapy is usually part of a larger cognitive behavioural therapy treatment. You can check in to see if there are any health providers that are trained in cognitive behavioural therapy for insomnia in your community.
Feature photo credits: Photo by Quin Stevenson on Unsplash