Lower Back Pain When Lying Flat On Your Back

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Load bearing is a major aggravating factor for most with lower back pain. The more load that you put on your back the worse it gets. For example, standing or walking, carrying and lifting, and even sitting all put more strain on the lower back to varying degrees. This extra stress on the injury can make lower back pain, and sciatica, more pronounced and painful. For most, this pain is relieved by reducing the load the back has to bear, laying down therefore is normally a relief. However, for some people, lower back pain comes on in a big way when you lay flat on your lower back, or the sciatica nerve pain you experience shoots into your leg as soon as you lie down. Today we will go through some explanations for why this happens and help you understand how to move forwards safely and resolve your back pain by addressing the root cause and injury.

The two most common reasons for back pain when you lie down

There are really two main reasons that could explain why you’re experiencing an elevation in your lower back pain or sciatica symptoms when you lie down.

  • Your lower back is flattening out as you lie down
  • Your lower back is pulled into an excessive arch as you lie down

At their root, these stem from instability which is the result of an injury to a joint. When we injure the low back or knee or any joint for that matter, it is the structures that provide integrity to that joint that allow it to function properly. For example, it is the screws that hold the hinges of your door in place tightly to the wall that keep the door functioning correctly. When those screws fail the door is rickety, wobbles, rubs on the floor or surrounding frame creating more damage and aggravation. At the root, back injuries are no different and this loss of integrity can mean for some, that there is unwanted movement that occurs when lying down, creating the pain.

Excessive inflammation in the lower back can also lead to an exacerbation of symptoms, particularly in cases of sciatica, where this “congestion” leads to more pressure being put onto the nerve as the spinal spaces get smaller when this unwanted movement occurs. 

We’ll explore these concepts a little more as we go into each of the examples.

Your lower back is too flat when you lie down

Over the years, and thousands of patients and sets of spinal imaging, MRI and X-rays, one of the things we have found is that those with persistent lower back pain tend to have a reduction in the natural curve of their lower back. We covered the best spinal position for a bad lower back in a dedicated episode of the podcast, suffice to say, a normal lordosis of adequate proportion is essential for optimal low back health. Reasons for this are simple, and this is primarily down to the significant amount of time spent sitting every day. Our bodies essentially mold to our chairs and you see the effect of this in our spine. 

When your lower back injury is “active” and there is tissue damage, there are two ways in which the lower back gets aggravated as it flattens out and you lie on your back. Firstly and surprisingly, so many people will still sit on the bed or floor and slowly lower themself from sitting into lying down, this creates a rounded position flattening the lower back even more as they lie back down, maximally driving compression through the lower back, increasing load. Then as you get to flat you have aggravated the injury and so it flares up over the ensuing moments and perhaps longer, especially in the more unhealthy spine. For these cases, it is not so much the lying down flat that causes the back pain to get worse, but how you got into the lying down position.

The secondary example is two fold and this is assuming you got into the position with proper form and technique so as to minimise the aggravation of the lower lumbar spine. This is that lying on your back without lordosis support results in the gentle stretching of the tissues in your lower back that are trying to tighten up and heal, disrupting a healing process and subtly aggravating the ligaments and discs that are injured. Like a frayed rope, with a gentle pull it steadily unwinds itself and worsens the fray. 

Generally speaking, those who are suffering from pain because their back is flattening out will experience more of a dull aching, which can intensify to be more of a throbbing.

Your lower back is arching too much when you lie on your back

This opposite scenario typically gives rise to more sharp pain locally, possibly shooting into the leg with sciatic type symptoms. Often this is much more severe in terms of the intensity of pain. Again, at its core, this scenario is down to instability allowing joints to be influenced, however there are commonly a few additional considerations here to point out. 

Severe instability in the lower lumbar spine causing the pain

One of the causes of the sharper sensations that you can experience here tends to be associated with hinge points in the lower back. If you look at a healthy normal spine we see that the neck has a backward bending curve which smoothly flows into the thoracic spine and rib cage which has a smooth forward bending curve, then into the lower back again which has another smooth backward bending curve finally into the sacrum which curves forwards again. All of these transitions should be smooth and you could imagine it being a pleasant experience if you were to go down a “waterslide” that was this shape. Unfortunately for some, usually associated with some sort of trauma or an accident of significant force, you can find a hinge point at the junction between the L5 vertebra and the S1 vertebra. One might imagine if this were a waterslide you would steer well clear as the bend at this junction would be a “hard left”. 

In these individuals it is common that movement does not really flow effectively through the lumbar spine above, instead things hinge at the L5, S1, so as they lie onto their back, instead of all the joints moving, the one, L5, S1 hinges backwards further and creates the aggravation! We’ll explain more about this in a moment. 

Tightness in the hip flexors pulling on your lower back as you lie down

We’ve already mentioned that sitting is far too prevalent in today’s society, many working age adults spending upwards of 9 hours a day sitting down! Without appropriate and proportional efforts to counter this with exercise, a problem for another podcast. One of the issues with this is the tightness that can develop in the hip flexors, these muscles pull your thigh bone up driving your knee closer to your head. As a result of stiffness, they can limit the proper extension of the hip joint, meaning that standing, or lying straight becomes problematic. 

As you lie down on your back, these hip flexors tug on the lumbar spine pulling it forwards into a “hyperlordotic” position. If we are unlucky enough to have the issue with a hinge point mentioned previously this can be decidedly more pronounced. 

The problem of hyperlordosis or extension when lying flat on your back

The primary issue with this specific movement is that it pulls the spine into a position where the little holes called “exit foramina” get smaller than in a neutral position. If there is inflammation built up in the lower back, which there will be if you have a back injury, this narrowing of the hole, a temporary form of spinal stenosis if you will, puts pressure on the exiting nerves. A relatively sudden “pinching” of the nerve’s results in what is often sharp and shooting pain, either in the back itself, or into the buttocks or leg. 

There are some additional considerations here that can help explain the particular sensitivity to this phenomenon. If we first understand that the extension itself in a healthy, but injured spine, can be enough to aggravate the back pain when lying down, then these can make this even more pronounced.

  • Disc herniations: these herniations or bulges can occupy some of that exit foramina, and therefore mean that the space is already smaller before the extension movement took place.
  • Facet hypertrophy: enlargement of the facet joints with bony spurs which encroach on the exit foramina will also further reduce the space before extension takes place.
  • Spondylolisthesis: this alters the shape in a more pronounced way and again affects the starting point, making any additional narrowing only more likely to be provocative.
  • Degenerative disc disease: spinal discs act as the spacers preserving a large exit foramina, if the discs have degenerated and lost height, this makes the starting point less favorable, even before we lie down and our back is pulled into extension.

These are just a few examples that can intensify both the level of the pain and its immediacy as you lie onto your back. Because it frequently relates to the compression of the exiting spinal nerves, compared to the flattening of the lumbar spine, it seems to be more commonly associated with sciatica or referred pain into the buttock, or leg. 

Lower back pain when sleeping

Much like the previous examples, the pain that you might experience when lying down in bed will have the same root causes, a spinal movement at the level of the lower back where the injury is placed. This tends to be why people opt for a more stable mattress when they have back pain, rather than a soft and fluffy one. Fundamentally however one of the big factors that you must address if you get back pain when sleeping is your evening routine and daily activities. 

A helpful example is to think of a sprained ankle. You might go over on the ankle while you’re out, straining the soft tissues in a relatively minor way. You think everything is ok, and it is only when you get back home and have been sitting down for 15 – 30 minutes that you look down and see your ankle is the size of a small balloon! There is this “delay” in inflammation, primarily because the small amounts of movement that you’re doing while still up and about help drain the excess inflammation being driven to the region. The same is true for your lower back.

If you struggle with back pain when sleeping, the best thing you can do first is to assess your daily routine and see if you’re doing the right things or unwittingly making things worse each day. We talk at length about combating lower back pain and sciatica when sleeping in the dedicated podcast so be sure to check it out when you get a chance if you’re struggling.

Relieving lower back pain when lying flat on your back

One of the best activities that everyone can do for their lower back pain is the towel stretch for lower back health. Particularly if you have pain when lying flat on your back, the towel works in a couple of important ways:

  • It supports the natural spinal curve in the lower back.
  • It holds the spine in a position approximating neutral, not flattened or extended!
  • It normalises spinal movement preventing hinge points.
  • It puts a gentle stretch through your spine taking pressure off the discs.
  • It unloads the ligaments and muscles that are often tight and tired.
  • It is free and easy to do for everyone!

This is just a simple and easy stretch to help you in the moment provide some decompression to the lower back and normalise spinal movement as best as possible at home, making lying flat on your back less painful. However, if you’re only getting pain when you lie down you’re probably getting the early warning signs that something in the lower back isn’t quite right. 

Early warning signs for lower back injuries

If there is one main thing we’ve noticed over the years it is that low back pain is a problem that is ignored for as long as possible. Most people do not have a severe injury or accident at the origin of their back pain. It just crept up over the years and was not dealt with when it was a small problem.

Do not make this mistake. 

If you’re lucky enough to only experience back pain or sciatica in this small moment and it is not an issue at other times of the day, count yourself lucky and take stock of whether or not you have been taking care of your lower back health. If you could do a better job then read on!

Re-building a strong & healthy lower back at any age

Fundamentally your requirement is not to stretch, it’s not to use pain relief, it is to strengthen and rebuild integrity to your lower back. This is what a healthy lower back is. It is also not endless pilates or yoga, not to say that they are not without merit, as they can help you build a strong core, but that is not synonymous with a strong lower back.

Work the foundations of core control to learn to build core competence, this is to be able to control and maintain the neutral position in your lower back. This could mean starting out with the simple exercises we teach in the Back In Shape Program, such as the modified dead bug, or marching bridge.

As you build competence in the off weight environment, you transition to on weight. Movements like the squat, hip hinge and lunge are staple life movements that we all must do, no matter your age! Yes even in your 80’s and older, if you want to be able to get out of a chair or go up stairs these movements are essential. 

They are essential to autonomous independence for a human being of any age. As a baby we cannot do these movements and so are heavily dependent on others to look after us, this is also true at the other end of life if we lose the ability to do these movements too, our independence takes a huge hit!

The final step is to use resistance, load, and weights in order to build tolerance in the joints, bones, muscles, tendons and ligaments of the body and spine. So long as you do this in a sensible and safe way, prioritising an initial technical competence, you will find you can not only resolve your lower back pain, but keep your back healthy and resilient to strain for the long term.

If you’re unsure where to start or want help to do this in the safest and most effective way, with expert support from our team every step of the way then check out membership to the Back In Shape Program below.

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