Clients spend 30% of their lives sleeping, so what happens at night is critical to optimising their ability to recover, both physically and mentally. While we regularly discuss clients’ diurnal loads, there is a significant gap in our understanding regarding their nocturnal loads. Our research has shown that we can’t rely on clients’ self-reports to inform us of their sleep postures accurately. (Impact-Site-Verification: f856beb9-f9a9-459a-acb0-4af887120bb4)
A key issue to date for clinicians is the lack of research examining sleep posture and waking spinal symptoms. Our group conducted a scoping review titled “Identifying relationships between sleep posture and non-specific spinal symptoms in adults: A scoping review,” which was published in BMJ Open in 2019. We found only four articles addressing this topic. Not much on which to base clinical decisions! One of the reasons for this was the lack
of a low-cost, portable method to assess sleep posture, especially in the home environment, where most sleep-related activities occur. As clinicians advising clients, we were particularly interested in the plausible biomechanical load that a client’s spine experiences at night, with key movements associated with rotation and extension.
My PhD focuses on sleep postures and their impact on waking symptoms and sleep quality, aiming to identify both provocative and non-provocative sleep postures and to determine whether, as clinicians, we can influence them and, if so, how. You would think that we would have a good understanding of sleep posture, but given the findings of our scoping review, it is clear that this was unexplored territory. We needed to classify sleep postures, locate suitable imaging equipment, develop and test a sleep posture recording protocol in the home environment, determine if people who woke up 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 involved a pilot study to gain an understanding of this relationship and to determine how we could measure sleep posture in our clients’ typical sleep environments.
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 unable to accurately self-report their sleep posture (hence the need to video them). While not statistically significant, it was noted that participants who spent more time in a supportive side-lying position had fewer mornings with symptoms per month than those who slept in a provocative side-lying position. This provided a plausible reason to continue pursuing the idea that biomechanical load influences waking spinal symptoms.
We determined that our recording protocol was robust and effective, as evidenced by the good footage obtained under sometimes ‘challenging’ environments, despite issues such as children, pets, and camera failure. Other technical issues with equipment and sleep posture classifications were resolved.
Sleep posture is classically described as supine, prone, and everything else is side-lying. Under this classification, we spend approximately 60-70% of our sleep time in a side-lying position. A problem with this classification structure is that it doesn’t account for the wide variety of side-lying sleep postures, some of which are potentially provocative to spinal load, while others are not. For this reason, we wanted to subclassify the broad side-lying category based on spinal loading into two subcategories, provocative and supportive side lying. With the footage obtained, we can accurately identify the cardinal sleep postures and the new sub-classified provocative and supportive side-lying postures.
The validity and reliability of equipment that assesses sleep posture in the home environment had not been previously determined, especially when considering the potential biomechanical effects of spinal rotation and extension in the side-lying position. We created a ten-minute video of sleep postures under various conditions of bed coverings (none, sheet, and sheet + duvet) to simulate a realistic home situation, as well as different lighting conditions (natural light and infrared light). Unique to our protocol was the use of two cameras in two different viewing planes. 20 health professionals viewed this video, and each sleep posture was scored. We found that both the intra- and inter-rater reliability were excellent. This means clinicians can use the protocol to accurately assess sleep posture in the home environment.
The fourth paper in our series of sleep studies compared symptomatic individuals (with neck or lumbar pain) and our control group across a broad range of pain, sleep, and quality of life measures. This research aimed 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, published in PLOS One.
While we suspected that people sleeping in specific postures could be a factor in provoking waking spinal symptoms, we were surprised to find that this also reflected in their sleep quality. When sleep quality is negatively affected, it has flow-on effects to a much broader range of health outcomes, including memory & learning, fertility, maintaining a healthy body weight, cardiovascular health (such as high blood pressure, heart attacks, and strokes), and workplace injuries. In addition to preventing waking spinal pain, improving sleep posture can 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 can change their sleep posture when asleep, and if they 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 in 2025.
