My PhD focuses on sleep postures and their effect on waking symptoms and quality of sleep, with the goal of identifying provocative and non-provocative sleep postures and whether as clinicians we have the ability to influence them and how. You would think that we would have a good understanding of sleep posture, but given the findings of our scoping review, clearly this was unexplored territory. We needed to classify sleep postures, find imaging equipment, develop and test a sleep posture recording protocol in the home environment, determine if people waking in pain slept differently and create and test the effectiveness of a simple education intervention to change sleep posture habits.
The first part of this process was a pilot study to gain some understanding of this relationship and how we could measure sleep posture in our clients' normal sleep environment.
Our 2016 pilot study titled, Examining the Relationship between Sleep Posture and Morning Spinal Symptoms in the Habitual Environment Using Infrared Cameras was a sample of convenience (i.e. whoever we could convince to have cameras set up in their bedroom!). It showed that people are not able to self- report their sleep posture accurately (hence the need to video them) and while not statistically significant, it was noted that participants who spent greater periods of time in supportive side lying, had less mornings with symptoms per month than those that slept in provocative side lying. This gave us plausible reason to continue to pursue this idea of biomechanical load influencing waking spinal symptoms.
We determined our recording protocol was robust and effective with good footage obtained under sometimes ‘challenging’ environments with children, pets and camera failure being some of the issues. Other technical issues with equipment and sleep posture classifications were ironed out.
Sleep posture is classically described as supine, prone and everything else is side lying. Under this classification, we spend approximately 60-70% of sleep time in side lying. A problem with this classification structure is that it doesn’t account for the wide variety of side lying sleep postures, some being potentially provocative on spinal load, while others are not. For this reason, we wanted to sub-classify the broad side lying category based upon spinal loading into two sub categories, provocative and supportive side lying. With the footage obtained, we are able to accurately identify the cardinal sleep postures and the new sub-classified provocative and supportive side lying postures.
Determining the validity and reliability of equipment that assesses sleep posture in the home environment had not been done before, especially when focusing on the possible biomechanical effects of spinal rotation and extension inside lying. We created a ten minute video of sleep postures under different conditions of bed coverings (none, sheet, sheet + duvet) to simulate a realistic home situation, and different lighting (natural light and infra red light). Unique to our protocol was the use of two cameras in two different viewing planes. This video was viewed by 20 health professionals and each sleep postures was scored. We found both the intra- and inter-rater reliability were excellent. Meaning, clinicians can use this protocol to accurately assess sleep posture in the home environment.
The fourth paper in our series of sleep studies compared symptomatic (neck or lumbar) and our control group across a broad range of pain, sleep and quality of life measures. The aims of this research were to compare sleep posture and sleep quality in participants with and without waking spinal symptoms. This is the first study using a validated objective measure of sleep posture to compare symptomatic and Control group participants sleeping in their home environment. In general, we found that participants with waking spinal symptoms spent more time in provocative sleep postures, and experienced poorer sleep quality. This paper is titled Examining relationships between sleep posture, waking spinal symptoms and quality of sleep: A cross sectional study and published in PLOS One.
While we suspected that people sleeping in certain postures could be provocative of waking spinal symptoms, we were surprised to find that this also reflected through to their sleep quality. When sleep quality is negatively affected, this has flow on effects to a much broader range of health outcomes like; memory & learning, fertility, maintaining a healthy body weight, cardiovascular health (high blood pressure, heart attack, stroke) and workplace injuries. So in addition to preventing waking spinal pain, improving sleep posture could also be an important aspect in a range of other health domains.
Current Research
In our most recent study, we used a sleep educational package in a longitudinal study of symptomatic participants (neck and low back pain), to determine ;
- If participants are able to change their sleep posture when asleep and if the can,
- What changes are noted in their regular waking spinal symptoms and
- Validated baseline quality of life, quality of sleep and spinal disability questionnaires.
Data has been collected and analysed, and will be written for manuscript submission or conference presentation.
The Sleep Mastery Online Course
Available in 2021, to assist clinicians translate this research into actionable clinical practice, key information from this research will be combined with sleep hygiene training, cognitive behaviour therapy training and validated outcome questionnaires and presented as the The Sleep Mastery online course. If you are an early adopter of new research, you can enrol in this course here.
