Cognitive Behavioral Therapy for Insomnia Part 4: Sleep Restriction
Sleep restriction can deepen and consolidate sleep.
Posted July 13, 2009
Matt was lying awake in bed, again. It was 3:30 a.m. His wife and young children were soundly asleep. The hours passed slowly. Thoughts drifted through his mind as he reviewed the day's events. The next morning he could not remember clearly what he had been thinking about all those hours in bed. This night was like so many others he had experienced over the years.
Matt was going through what many people with insomnia experience. While he felt that he was awake for hours on end, more likely he was drifting in and out of light, stage one sleep and drowsy wakefulness. In stage one sleep it is possible to be aware of continued cognitive activity and believe that you are actually awake. This sleep gives some benefit, but is not highly restorative. Specific techniques have been developed to cope with this type of poor sleep. They focus on the concept of sleep efficiency. Sleep efficiency is defined as the percent of time spent in bed asleep.
Sleep restriction was developed by Spielman and his colleagues in the 1980's as a means of limiting time in bed to the actual amount of sleep obtained in order to increase sleep efficiency. Decreasing time in bed thus maximizes the percentage of time spent actually sleeping. After sleep has become deeper and more consolidated, time in bed is then gradually increased unit an optimal duration is reached.
Sleep restriction, or perhaps more accurately, bed restriction, is based on the assumption that sleep deprivation will increase the drive to sleep and to remain asleep. This may not fit with the experience of those with insomnia for whom sleep seems impossible no matter how long they have not slept. It does make sense, however, when you consider that people with insomnia often underestimate the amount of sleep they are getting, in part because they misinterpret light sleep as wakefulness. Another effect that sleep restriction has is to break up the relationship between being in bed and being awake. Over time, being in bed while awake can lead to conditioning effects such that the bed becomes a conditioned stimulus for arousal. By limiting the amount of time in bed to approximately the amount of time spent sleeping, the bed becomes a conditioned stimulus for sleep. Just getting in bed can then elicit sleep rather than arousal.
Initially the amount of time in bed is reduced to close to the average number of hours usually slept. The amount of sleep is determined by keeping a one to two week sleep journal as previously discussed. The assumption is that most insomnia patients underestimate the amount of sleep they obtain. If time in bed is restricted, sleep will also be restricted. Sleep drive will be increased and light, poor quality sleep will be decreased as greater sleep drive causes deeper sleep. This will result in increased sleep efficiency and fewer awakenings as sleep consolidation increases during the more limited time spent in bed. Over several nights the impact of this technique can be dramatic and often results in significant improvement in the quality of sleep. The full benefit of this technique may take several weeks to be realized.
As sleep becomes more consolidated and sound, it is possible to gradually go to bed earlier or possibly to sleep later by about 15 minutes a week until an optimal amount of sleep is reached. It is appropriate to increase time in bed once sleep efficiency has risen to about 85% and this level of sleep efficiency is maintained for several weeks. Some experimentation may be needed to determine the best bed time and morning rise time. It is generally best to set a fixed morning rise time that is maintained throughout the week including weekends and vacations and work backwards to a bed time based on the allotted number of hours of sleep. Normal sleep efficiency is about 90%. Once sleep efficiency has risen above 85%, awakenings have been reduced and no further improvement is gained by going to bed earlier or sleeping later, an optimal bed and rise time will have been determined.
It may be necessary to use light physical activity to stay up until the scheduled bed time. For example, avoid sitting in front of a TV if in the past there has been a tendency to fall asleep on the couch with subsequent lying awake after going to bed. In the hour or so before bed time begin to "wind down" by engaging in relaxing activities such as listening to music or doing relaxation techniques.
Sleep restriction is often best done under the supervision of a behavioral sleep therapist as it is contraindicated in people who have excessive daytime sleepiness. This is due to potential safety issues that may arise with sleep restriction such as drowsy driving, triggering seizures in people with seizure disorders, and possible negative effects on mood in people with bipolar disorder. With appropriate supervision, sleep restriction can transform "tossing and turning" into consolidated, sweet, refreshing sleep...