By Jan Willem Elkhuizen
There is a lot of attention nowadays for exercise. And rightly so! It keeps the body healthy and in shape. Much less attention is given to posture and even less to sleeping posture. While a good sleeping posture is very important and can prevent physical complaints.
Static loading
What static loading (i.e., without movement) can lead to can be experienced by anyone by doing the following:
Sit in a comfortable chair with your feet on a footstool. The legs are relaxed and the knees are straight and hang slightly in the end position.
After some time, the knees become a bit sensitive. The urge arises to change position. However, if you do not do this, the unpleasant feeling grows stronger and becomes really painful. When you then stand up, it is difficult and you cannot move easily at first. The knees are stiff. After a while, it gets better again and there is no more problem.
What is actually happening here?
In this position, the ligaments are tight. They stretch very slowly a little bit. This is called creep mentioned. These ligaments are made up of collagen fibers, a kind of rope. They ensure that the bone pieces are firmly connected while also allowing them to move well relative to each other. Good ligaments are essential for joint function. If the ligaments are somewhat stretched, this can lead to joint complaints.
Collagen fibers are found not only in ligaments but also in intervertebral discs (more on this later). Static loading can therefore also affect the back.
The image below is from a 1992 study by McGill. It examined the effect of holding the spine bent for a period of time.
Figure 1. A force is applied to the spine. It bends as far as it can. In the next 20 seconds, the bending slowly increases. Creep occurs in the fibers of the intervertebral disc. After 20 minutes, the load is removed and the tissue recovers. After 50 minutes, the creep is largely restored.
What do we learn from this? First, that something is indeed happening to the body, even though from the outside it seems like nothing is happening. The fibers in the intervertebral discs gradually stretch. Second, that recovery takes quite some time: the recovery time is longer than the duration of the load.
Straining sleeping position
If the neck or back is under tension during sleep, creep also occurs. Just like in the image above and also like in the example with the knees.
Figure 2: sleeping on the stomach. The neck is turned. The collagen fibers in ligaments and intervertebral discs are under tension. This is a case of static loading.
The sleeping on the stomach is enormously stressful for the neck. The neck is twisted and the fibers in ligaments and intervertebral discs are under tension. It is not surprising that people sometimes wake up with a somewhat stiff neck after sleeping on their stomach.
Slightly less severe, but very common and therefore all the more insidious is this sleeping position:
Figure 3: sleeping in the three-quarter position
Many people sleep on their side. At least, that is what people think. In fact, people almost never really lie well on their side, but more somewhere between side-lying and stomach-lying. This is called the three-quarter position mentioned. This sleeping position is also very stressful for the neck. It is probably even the most common cause of unexplained chronic neck complaints and tension headaches.
That may seem a bit exaggerated, but there is strong evidence that it indeed causes so many complaints. That is not surprising:
1) The head is turned relative to the torso. Ergo: the neck is twisted.
2) The head lies higher than the torso. Ergo: the neck is bent sideways.
And it is precisely the combination of rotation and lateral bending of the neck that causes problems. Both movements have the same effect on the joints between the 2e and 3e neck vertebra. Because of this, these joints quickly reach their end positions. And it is precisely in the end positions that the fibers in ligaments and intervertebral discs are under tension! In addition, the ligaments between the skull and the neck are also under tension in this sleeping position.
This leads to sleeping in the three-quarter position causing neck stiffness, neck pain, and headache.
Cervicogenic headache
Headache where the cause lies in the neck is called cervicogenic headache. This includes a large part of the common 'tension headaches'. It often manifests as headache combined with neck complaints, but not always! Especially in the latter case, it is often not recognized that the cause of the headache lies in the neck.
People just have a headache, for example above the eyes or like a band around the head. Without clear signs of neck problems. People often go for years like this going around without anyone telling them that it comes from the neck and what you can do about it. Extremely frustrating, especially because the impact of chronic headaches is often so great.
Cervicogenic headache that is truly primarily caused by a wrong sleeping position often develops as follows:
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It starts 'just like that', without a clear reason;
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It starts with a somewhat strange feeling and sometimes a slight headache;
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In the beginning, it also takes some time again;
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The symptoms increase in frequency and intensity over the years;
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It can end with daily severe headaches, sometimes even migraine-like symptoms;
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The headache is already present upon waking and/or shortly after getting up. It may lessen during the day or even disappear completely;
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Sometimes there is also a bit of neck stiffness. When looking maximally over the shoulder, one usually feels the ‘pulling of muscles.’ Often without these muscles themselves being really painful.
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The manifestations of cervicogenic headache are very diverse. This is because many muscles, ligaments, nerves, and other tissues can cause headaches, each with their own radiation areas in the head.
Figure 4: The manifestations of cervicogenic headache are very diverse.
Many people have been sleeping in a wrong position for years before symptoms appear. That is why the link with a wrong sleeping position is often not made. After all, nothing has changed compared to the years before the symptoms appeared!
It is also common for someone to have had an accident where the neck was forced. For example, from a fall, walking into a lamppost, or a car accident. Often resulting in injury to the ligaments between the head and neck. A wrong sleeping position is then not the primary cause but can lead to slower recovery or even worsening of symptoms.
Chronic back pain
Many chronic back complaints originate in the intervertebral discs low in the back.
Figure 5: The location of the lower intervertebral discs of the back.
If we zoom in on the intervertebral disc (also called a discus), it looks like this:
Figure 6: A disc consists of a gel-like core surrounded by about twenty lamellae with fibers. These fibers are crossed per lamella.
The problem with the intervertebral discs is that the gel-like core (shown in red in figures 5 and 6) can leak through the lamellae. This pulp-like substance then gets between the lamellae and can cause chronic pain, back stiffness, and cause misalignments. The larger the leakage and the further it has progressed toward the outer lamellae, the more symptoms there are.
Beginning tear Tear halfway Hernia
Figure 7: Viewed from above, we see the different stages of leakage or tearing of the lamellae. If the red-drawn gel-like material from the core has leaked through all lamellae, then it is a hernia.
What does sleeping position have to do with chronic back pain?
Two factors are important here:
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If tension arises on the fibers in a disc during sleep, the elasticity of those fibers decreases. The back becomes stiff from this. This can occur, for example, in such a position:
Figure 7: The legs are crossed, causing rotation in the lower back and tension on the fibers in the disc.
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If the back is not in a neutral position, the pressure and tension in the intervertebral discs increase. Leaks in the disc can therefore increase. A mattress that does not fit the weight and shape of the body can contribute to this.
Figure 8: If the mattress sinks enough under the pelvis and shoulders but not too much, a neutral position of the spine is created.
The recommended sleeping position
It will be clear that it is very important for the neck and back to get rest during sleep. They can then recover from the strain of the day. The intervertebral discs gradually compress during the day and recover again at night. That is why we are over 1 cm taller in the morning than in the evening.
For good recovery, it is necessary to avoid static load. That sounds a bit complicated, but the solution is actually surprisingly simple. Sleep with a body pillow between the knees! Choose a head pillow that fits well with the neck and head, and also a mattress that suits the weight and body shape.
If everything is optimally adjusted, this is the result:
Knees, hips, pelvis, lower back, shoulders, and neck are all in a neutral position. Tensions are minimal, and the body can recover during the night as it should.
gezondNU Research
The monthly magazine gezondNU conducted a study on the effect of ‘sleeping differently’ among 89 readers of their magazine. They went to sleep with a Mikoala Body pillow combined with a Hi4 head pillow, the height of which was adjusted to fit the test subject. This corresponds to the optimal sleeping position shown above.
Positive effects were found in various areas:
1. People slept better and woke up less often
2. People felt better rested in the morning
3. The number of days with headaches decreased on average by over 45%.
4. The number of days with neck pain decreased by 71%
5. The number of days with back pain decreased by 39%
6. The stiffness in the neck and back decreased
7. The sleeping position improved. Less on the stomach, less ¾ position, and more on the side.
Some charts from the research report:
