If you’ve read the sleep hygiene information I posted yesterday, you’ll read that it’s not a good idea to stay in bed if you’re not asleep. Here’s another version. Beds are for sleep and sex, not for being awake – because our brains are very good at learning to put two and two together to come up with PING! Bed = Awake. Much of the sleep hygiene approach involves reducing the association between stimulus and response, and by reducing any influence of stimulants, or factors that interrupt the sleep architecture.
For a great review of CBT approaches to sleep problems in people with chronic pain, Nicole Tang has written a nice review looking at various aspects of sleep and pain – and the CBT approaches that have been recommended and studied. But – I’m not going into detail about this paper, that’s your job. Today instead I want to look at one of the first studies into the use of sleep restriction as a therapy for insomnia, written by Spielman, Saskin and Thorpy in 1987. I’m doing this because the paper they wrote discusses some of the underlying principles for using sleep restriction – and the paper clearly describes how to go about the intervention.
Sleep restriction is based on the idea that one of the factors that maintains insomnia is staying in bed while not sleeping. Simply put, sleep restriction involves setting your bedtime by establishing the number of hours you actually sleep and going to bed that same number of hours before you intend to (or ordinarily) get up. By introducing a little bit of sleep deprivation initially this approach increases the likelihood you’ll fall asleep quickly – consolidates the sleep actually achieved, producing daytime fatigue that may reduce the hyperarousal that people with sleep problems often have, and also minimise the time spent in bed wide awake.
Another aspect of this approach is to ensure the consistent bedtime, and more importantly, the consistent wake-up time, reduces the anticipatory anxiety many people experience when they’ve had trouble with sleep – that ‘Oh no, will I ever get to sleep tonight’ thought chain.
In this original study by Spielman, Saskin and Thorpy, participants in the study recorded their sleep pattern for two weeks prior to the intervention. The ‘average subjective sleep total sleep time’ was used to calculate the amount of time in bed used at the start of the programme. For example, if the person thought they achieved a total of 5 hours sleep each night, at the beginning of the programme the ‘time in bed’ was set at 5 hours. The wake-up time was set according to normal work schedules, so the person only went to bed 5 hours before they were due to wake up. No person was required to have less than 4.5 hours time in bed.
Over the eight weeks of this programme, participants recorded their total sleep time, the time they went to bed, and their wake-up time in the morning. From this data, ‘sleep efficiency’ was calculated – this is the ‘estimated total sleep time/time in bed x 100%’, combined with the sleep efficicency values for the previous 4 days, to arrive at a mean over 5 days. This calculation was then used to guide the sleep schedule changes – with some very specific guidelines.
(1) When the mean sleep efficiency over the previous 5 days was 90% or more, then the person was able to add 15 minutes to their total time in bed – in other words, go to bed 15 minutes earlier
(2) When the mean sleep efficiency over the previous 5 days was less than 85%, the time in bed was reduced – but not until 10 days after the start of the treatment, or for 10 days after a change had been made to the sleep schedule. Time in bed was reduced to the mean sleep time over the previous 5 days.
(3) If the mean sleep efficiency was between 85 -90%, then the time in bed wasn’t altered.
The only other ‘rules’ were not to lie down or nap at anytime other than bed-time. There were no changes to caffiene intake, food, tobacco, exercise or even whether to stay in bed when they weren’t able to sleep.
Using ANOVA, baseline and end of treatment analyses were carried out. Time in bed, sleep latency (how long it takes before falling asleep once in bed), total time awake, total sleep time and sleep efficiency (as previously described) were all analysed. The results looked good – mean total sleep time over the group of 32 participants went from 320 minutes to 343 minutes, (P<0.05), sleep efficiency went from 67% to 87%, and the time it took for people to fall asleep went from 48 minutes to 19 minutes.
What can we conclude from this?
Well, this study was quite small, the participants were not people with chronic pain, and the follow-up period was weeks rather than months. The drop-out rate was also reasonably high, and there were comments about difficulty complying with the instructions. All of which means it’s important not to draw too many conclusions from this study alone – thankfully, however, sleep restriction has been studied in much more depth since this original work.
I’ve written in detail about the procedures used in this study, because so often it’s difficult to find out exactly how to carry out a specific strategy like sleep restriction.
Practical problems that were found in this study haven’t really changed much – I’ve had people not carry on with sleep restriction because ‘it annoys my husband’, ‘I couldn’t function the next day when I tried to drop the kids off to school’, ‘I kept forgetting the time I was meant to get into bed’, ‘I kept falling asleep on the couch before my bedtime’ – and so on.
For people with whom I have used this approach successfully, what is surprising is how quickly their sleep pattern consolidated and they were able to maintain good sound sleep thereafter. Even during relapses into insomnia, the people who used this approach were able to quickly return to their sleep restriction and get back into a normal sleep pattern over days rather than weeks. It’s also a useful approach for people who don’t want to use medication for sleep, or who can’t use tricyclic antidepressants.
One interesting finding is that reduced pain doesn’t make an awful lot of difference to sleep quality – and vice versa, better sleep doesn’t appear to change pain all that much. What is different is the feeling of being more refreshed and more positive, making it easier to manage the pain. And that’s why I’ll still help with sleep problems as a priority.
More on sleep soon – stay tuned!
Tang NK (2009). Cognitive-behavioral therapy for sleep abnormalities of chronic pain patients. Current rheumatology reports, 11 (6), 451-60 PMID: 19922736
Spielman AJ, Saskin P, & Thorpy MJ (1987). Treatment of chronic insomnia by restriction of time in bed. Sleep, 10 (1), 45-56 PMID: 3563247