The Shocking Link Between Gut Issues and Lower Back Pain (And How to Fix It)

It is 3 a.m. You are doubled up on the bathroom floor again. By the time you crawl back to bed, your lower back is throbbing and you cannot tell anymore where the gut pain ends and the back pain begins. Or you have been constipated for four days, your stomach feels like a brick, and your lower back has joined the party with a dull, immovable ache that no stretch is touching.

If that pattern is familiar, you are not imagining the connection.

THE SHORT VERSION

The gut and the lower back share parts of the same nervous system wiring, which is why digestive problems can produce real back pain. Constipation and diarrhea each do it in a different way. A landmark longitudinal study following thousands of women found that pre-existing gastrointestinal symptoms predicted the future development of back pain. Treating only the back when the gut is the driver is one of the more common reasons low back pain does not resolve. Fixing what is happening in the gut, and rebuilding the support structures around the spine, is what tends to work.

THE GUT AND THE BACK ARE WIRED TOGETHER

This is not a wellness slogan. It is anatomy.

The nerves that carry signals from your colon, bladder, and reproductive organs enter the spinal cord in the lower thoracic, lumbar, and sacral regions. The nerves that carry signals from the skin and muscles of your lower back enter the spinal cord at the same levels. In the dorsal horn of the spinal cord, those two streams of information converge onto the same second-order neurons. The brain, sitting at the other end of those neurons, cannot always tell which input came from which place.

That is the formal substrate for what doctors call referred pain. A 2015 study in the journal Pain showed that somatic and visceral C-fibers (the small nerve fibres that carry pain) converge monosynaptically (directly, in a single synapse) onto the same neurons in lamina I of the spinal cord. The pain pathways are not parallel; they are crossed. A 2023 review in Frontiers in Neurology compared it to "crossed telephone lines": the brain gets a signal that pain is happening, but the assignment to a specific body region can be off.

That is why a gut problem can show up as a back problem, and why treating the back without looking at the gut can be a losing strategy.

CONSTIPATION PULLS YOUR BACK INTO THE MESS

A backed-up colon is not a passive thing. It distends. It exerts pressure on the structures around it. The intra-abdominal pressure changes. The lumbar nerve roots that pass close to the colon get extra input from the distended tissue, and that input gets routed through the same spinal cord segments as your low back muscles.

Three things happen in your lower back as a result.

The colonic input increases the firing of the convergent dorsal horn neurons, which the brain experiences as pain in the lower back muscles even though those muscles are not the source. The body guards. Breathing patterns change, ribs lift, diaphragm moves less, and the back muscles work overtime to maintain posture against the abdominal pressure. The pelvic floor, which normally coordinates with the diaphragm, gets pulled into the bracing pattern.

If you have ever noticed that your back pain eases the day after a good bowel movement, this is why.

DIARRHEA DOES IT DIFFERENTLY, BUT IT DOES IT

The mechanism is different but the result is similar.

Diarrhea, especially when it is recurrent (an inflammatory bowel disease flare, an IBS-D pattern, a stomach bug that will not quit, a food intolerance) drives high-frequency nerve traffic through the same visceral afferents. The pelvic floor and core abdominal muscles brace repeatedly. The lower back muscles act as accessory stabilisers. Inflammation in the colon sends signals that converge on the same dorsal horn neurons as the back input. The result is a low back that feels strained, achy, and hard to settle even though there is no specific back injury.

A useful clinical rule of thumb: if your low back pain rises and falls with your GI symptoms, the GI symptoms are very likely involved. If the back pain is constant and unrelated to your bowels, the driver is more likely elsewhere.

THE STUDY MOST PEOPLE HAVE NEVER HEARD OF

This is the piece that should change how people think about back pain.

The 2009 longitudinal cohort study by Smith, Russell, and Hodges in the Journal of Pain followed almost 7,500 women from the Australian Longitudinal Study on Women's Health, all of whom had no back pain at the start. Over the following 2 to 4 years, the researchers tracked who developed back pain and what predicted it. Women with pre-existing gastrointestinal symptoms were 24 to 44 percent more likely to develop back pain than women without GI symptoms.

That is not a treatment study. It is a prediction study. It says, in plain terms, that the gut you have today helps predict the back pain you will have tomorrow.

That is also consistent with the clinical observation that patients with irritable bowel syndrome carry a high background rate of low back pain. A 2024 pilot study in Medicina on IBS-associated chronic low-back pain frames the link as a recognised clinical entity that often gets missed because IBS specialists treat the gut and back specialists treat the spine, and the patient sits in between.

WHY PAINKILLERS, STRETCHES, AND ADJUSTMENTS PLATEAU

Three common first responses to low back pain do not address the gut piece.

Painkillers (acetaminophen, NSAIDs, muscle relaxants) blunt the signal at the back. They can help in the short term. They do not change what the colon is doing, which means the input keeps coming. The pain returns when the medication wears off.

Stretching the lower back feels productive in the moment. If the back muscles are tight as a downstream response to abdominal pressure or pelvic floor bracing, stretching the muscles addresses the consequence, not the cause. The relief is short.

Spinal manipulation, on its own, has the same limitation. It can give a brief reset, but if the visceral input is still hammering the same dorsal horn neurons, the pain pattern often re-establishes within hours or days.

None of these is wrong. All of them are incomplete when the gut is part of the picture.

WHAT ACTUALLY HELPS

A real plan for gut-related low back pain has three parts that work together.

First: get the gut looked at properly. If you have ongoing constipation, diarrhea, abdominal pain, or unexplained changes in bowel habits, that is a family doctor or gastroenterologist conversation, not a physiotherapist conversation. We will tell you if we see signs that warrant medical follow-up before we treat anything else. Conditions like IBS, IBD, food intolerances, pelvic floor dysfunction, and endometriosis all have real medical management pathways, and the back pain often eases when the underlying gut problem is treated.

Second: address the musculoskeletal layer that has been built up around the gut problem. The repeated bracing, the bracing-driven breathing pattern, the pelvic floor over-activity, and the lower back muscles working as accessory stabilisers all become part of the pain picture once they have been running for months. They do not unwind on their own just because the gut starts behaving. They have to be retrained.

That is the layer we work on at Unpain Clinic in Edmonton. It includes:

• A movement and breathing assessment. We look at how you brace, how you breathe under load, how your diaphragm and pelvic floor are coordinating, and how the lumbar spine and hips are loading.
• Manual therapy and focused shockwave therapy for the muscles and tissues around the lower back that have become chronically tight or sensitised.
• A short, specific exercise program that re-coordinates the diaphragm, pelvic floor, deep core, and gluteal muscles. That is the load-sharing system the back actually needs.
• EMTT when broader regional pain is in play, and NESA neuromodulation when the picture suggests the nervous system itself has become sensitised.

Third: keep the daily habits that protect both systems. Hydration. Movement most days. A diet that supports bowel regularity. Sleep, which affects gut motility and pain processing both. These are not the glamorous part of the plan, but the back-and-gut loop is usually most stubborn in people whose lifestyle is feeding it.

WHAT WE DO NOT OFFER

We do not treat irritable bowel syndrome, inflammatory bowel disease, or any other primary gastrointestinal condition. We are physiotherapists and registered massage therapists, not gastroenterologists.

We do not prescribe diet plans, supplements, or medications, including laxatives, magnesium, fibre supplements, or anti-diarrheal medication. Those are conversations to have with your physician, a registered dietitian, or your pharmacist.

We do not perform injections or surgery. If your back pain has not responded to a thorough conservative plan and surgery is on the table, we will tell you and refer you to a spine specialist for an opinion.

We do not promise cures. Most chronic back pain improves with the right combination of treatments, but not every case resolves completely. What we offer is an honest assessment, a clear plan, and a team that will tell you if we are not the right fit.

“I was recommend by a friend to see Dr. Lacina Barsalou at the Unpain Clinic. I originally was only looking to treat a sports related wrist injury using shockwave therapy, but also took advantage to see if shockwave therapy could also heal my long term back injury.

I went in for 4 treatments so far, and the wrist healed back up within 2 treatments! I fell and hurt my back in 2020 during a slip and fall when hiking. I was only able to mitigate the symptoms by seeing a chiropractor and physiotherapist once every 4 weeks, but I was never fully healed or cured.

Lacina explained to me that I likely had scar tissue in my lower back, which is the reason that I need to have my back reset every once in a while, and it always felt tight.

However, the shockwave therapy breaks down the scar tissue so my back could go back to normal, and faciliate healing. My back muscles have been way looser and I have felt way better than before.

If you have a long term back injury, or a sports related injury, I really do recommend booking an appointment/consultation with Dr. Lacina Barsalou at the Unpain clinic to see if she can help you out.

I am lucky to have met her, and get treatment on my writst and my lower back.”- Vince Fung

FREQUENTLY ASKED QUESTIONS

Can constipation really cause lower back pain?

It can contribute to it. A backed-up colon distends the abdomen, increases intra-abdominal pressure, and sends visceral nerve input through the same spinal cord segments as your lower back muscles. The brain can experience that signal as back pain even though the back tissue itself is not the source. If your low back ache eases reliably the day after a good bowel movement, the gut is likely part of the picture.

Can IBS cause back pain?

Many patients with irritable bowel syndrome report chronic low back pain. A 2024 pilot study in Medicina on IBS-associated chronic low-back pain describes the link as a recognised clinical entity. The proposed mechanism is the same visceral-somatic convergence at the spinal cord that explains other forms of referred pain.

Should I see a doctor or a physiotherapist for gut-related back pain?

Both, in that order. The gut symptoms themselves are a medical conversation: family doctor or gastroenterologist. Once those are being managed, a physiotherapist addresses the musculoskeletal layer that has built up around the gut problem, including the breathing pattern, pelvic floor activity, and back muscles that have been overworking.

Will shockwave therapy fix the gut connection?

No. Shockwave is a musculoskeletal tool, not a gut tool. It can help the back muscles, fascia, and tissue around the lumbar spine that have become chronically tight or sensitised as a downstream effect of the gut problem. The gut piece itself needs separate medical management.

How long does it take for back pain to ease once the gut is treated?

It varies. Some patients notice the back ache settling within a few weeks of getting the gut under control. For others, the musculoskeletal layer has been running long enough that it does not resolve on its own, and a targeted physiotherapy plan is what closes the loop. A reassessment six to eight weeks into any plan is a reasonable checkpoint.

Do I need a doctor's referral to come to Unpain Clinic?

No referral is needed. Physiotherapists and registered massage therapists in Alberta are primary contact providers, so you can book directly. Some extended health plans require a doctor's referral for reimbursement, so it is worth checking your benefits.

What if my back pain is not related to my gut at all?

We figure that out at the assessment. Lots of low back pain has nothing to do with the gut, and we will not invent a connection that is not there. The point of a full assessment is to find what is actually driving your pain, whether that is a stiff thoracic spine, a weak hip, an old surgical scar, a sensitised nervous system, or a structural problem in the spine that needs a different specialist.

ABOUT THE AUTHOR

Written by Uran Berisha, PT, RMT, Founder of Unpain Clinic and Medical Shockwave Institute. Uran is a physiotherapist based in Edmonton, Alberta, and an International Educator in Shockwave Therapy. Medically reviewed by Uran Berisha, PT, RMT.

READY TO FIND OUT WHAT IS ACTUALLY DRIVING YOUR BACK PAIN?

If your low back pain has not responded to the usual stretches, painkillers, and adjustments, and you have been quietly wondering whether your gut might be part of the story, you may be right. The next step is a 60-minute one-on-one assessment in Edmonton where we look at the back, the chain around it, and the systems that interact with it. No referral needed. No pressure. We will tell you honestly whether our approach is the right call, and we will tell you just as honestly if you need to start with your family doctor instead. You can book a one-on-one assessment when you are ready.

REFERENCES

The following sources are linked inline in the body above. The full citations are listed here for completeness.

1. Smith MD, Russell A, Hodges PW. Do incontinence, breathing difficulties, and gastrointestinal symptoms increase the risk of future back pain? Journal of Pain. 2009;10(8):876-886. doi:10.1016/j.jpain.2009.03.003. PMID: 19409859. https://pubmed.ncbi.nlm.nih.gov/19409859/
2. Luz LL, Fernandes EC, Sivado M, Kokai E, Szucs P, Safronov BV. Monosynaptic convergence of somatic and visceral C-fiber afferents on projection and local circuit neurons in lamina I: a substrate for referred pain. Pain. 2015;156(10):2042-2051. doi:10.1097/j.pain.0000000000000267. PMID: 26098437. https://pubmed.ncbi.nlm.nih.gov/26098437/
3. Zhang Y, Hu J, Li Z, Li T, Chen M, Wu L, Liu W, Han H, Yao J, Zhang H. Referred pain: characteristics, possible mechanisms, and clinical management. Frontiers in Neurology. 2023;14:1104817. doi:10.3389/fneur.2023.1104817. https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1104817/full
4. Barassi G, Pirozzi GA, Di Iorio A, Pellegrino R, Galasso P, Heimes D, Praitano B, Gallenga PE, Prosperi L, Moccia A, Panunzio M. Quantum medicine and irritable bowel syndrome-associated chronic low-back pain: a pilot observational study on the clinical and bio-psycho-social effects of bioresonance therapy. Medicina. 2024;60(7):1099. doi:10.3390/medicina60071099. https://pmc.ncbi.nlm.nih.gov/articles/PMC11278534/