Sleep Efficiency is a measure of how consolidated your sleep is through the night which is a strong indicator of sleep quality.
Healthy sleepers have a Sleep Efficiency of around 0.85 – 0.90. Once your Sleep Efficiency starts dropping below around 0.80 on an ongoing basis. you are potentially going to start running into issues with your sleep.
There are a couple of reasons Sleep Efficiency is a useful measure of sleep.
1 - Poor Sleep Efficiency Is An Indication Of Insomnia
When someone suffers from insomnia they are generally spending excessive amounts of time in bed trying to get to sleep.
They will often take longer than 30 minutes to fall asleep, and this time will be spent lying in bed, desperately waiting for sleep to take hold.
Alternatively they may wake through the night and then struggle to fall back to sleep, potentially laying awake in bed for lengthy periods of time.
Where someone has ongoing issues with poor Sleep Efficiency they are generally suffering from insomnia.
2 - Poor Sleep Efficiency Can Also Contribute To Insomnia
A healthy sleeper has a strong association in their brain between being in bed and being asleep. They get in to bed and within 20 minutes they are sound asleep.
When you spend long periods of time awake in bed, it begins to weaken this association and can actually end up creating an association in your brain between being in bed and being awake.
For people who are suffering from chronic insomnia, this will be seen by the fact that they can be in the living room at night and start to feel drowsy but as soon as they get into bed they begin to become more alert again.
It is one of the most frustrating aspects of insomnia and.
Measuring Sleep Efficiecny
The formula for measuring Sleep Efficiency is very simple.
So for example, in a healthy sleeper it might take 15 minutes to fall asleep, They might wake once through the night and be awake for 15 minutes. And they might take 15 minutes in the morning after initially waking up to get out of bed.
So all up for the night they might get 7.5 hours of sleep from the 8.25 hours spent in bed.
This would give them a sleep efficiency of about 0.91 (7.5 ÷ 8.25).
Someone suffereing from insomnia on the other hand might take 1.5 hours to fall asleep. They could wake twice through the night for a total of 1 hour. And they might only get 5 hours of sleep from the 7.5 hours in total spent in bed.
This would give them a Sleep Efficiency of around 0.67 (5 ÷ 7.5).
More Accurate Measurement Of Sleep Efficiency
In the Comprehensive Sleep Assessment that you get your clients to go through, we get them to estimate their averages for time spent sleeping and time spent in bed in order to calculate their Sleep Efficiency.
But to get a more accurate measurement for Sleep Efficiency we would use a sleep diary which is the first thing we ask people to do as part of the 5 Weeks To Better Sleep program.
This lets us establish a baseline that we then use to create custom Sleep Scheduling to begin improving their Sleep Efficiency.
SCI – Sleep Condition Indicator
The SCI is a self-assessment tool used to identify the existence and severity of insomnia. The scale runs from 0 – 36. Lower numbers are indicators of more severe forms of insomnia.
This assessment is useful as a way of differenetiating people who are experiencing insomnia vs other issues with sleep.
Where clients are seen to have an SCI below about 18, you might want to consider recommending Cognitive Behavioral Therapy for Insomnia (CBT-i) via the '5 Weeks To Better Sleep' Course'.
For scores is single digits you would absolutely be pushing them towards this course.
So basically the lower the SCI, the stronger your recommendation to them should be.
What does it measure
Why is this useful