Marissa was a digital designer who loved working from home. The quiet. The focus. The freedom to stay in her flow state for hours.

But her back didn’t love it.

By mid-morning, her low back would ache. By the afternoon, she’d be shifting in her chair every five minutes. And by evening? She was lying on the floor, knees up, wondering why her body was punishing her for doing absolutely nothing.

She’d bought a fancy chair. Got a standing desk. Tried a lumbar roll. But the pain still came back—especially on days with long Zoom calls.

“Why does sitting hurt so much?” she asked when she came into my chiropractic office in Ashland, OR. “I’m not even doing anything.”

And that’s exactly the problem.

It’s not just that you’re doing nothing. It’s that your spine is built to move—and sitting sends the wrong signals to the system that protects you.

What Happens to Your Spine When You Sit Too Long

Let’s zoom in on the anatomy.

The lumbar spine consists of five vertebrae (L1–L5) stacked with intervertebral discs in between. Each disc is made up of a tough outer ring called the annulus fibrosus and a gel-like center called the nucleus pulposus. The disc acts like a hydraulic shock absorber.

Now, when you sit:

The pelvis tilts posteriorly, flattening your lumbar curve (reducing lordosis)
The spine enters sustained flexion, placing compressive and tensile forces on the posterior portion of the disc
The nucleus shifts posteriorly, creating added pressure on the outer annular fibers
The intradiscal pressure increases by up to 40% compared to standing, particularly in flexed, slouched positions¹

Over time, these mechanical changes can:

Fatigue the posterior ligaments and joint capsules
Irritate the facet joints
Create micro-tears in the outer annular fibers, leading to inflammation
Decrease hydration within the disc matrix, reducing its resilience²

Even worse? The spinal joints (zygapophyseal joints) stop moving. And when movement is lost, the brain gets less proprioceptive input from the mechanoreceptors embedded in those joints.

That’s when the pain system kicks in—not because you’re broken, but because your brain senses stagnation, threat, and loss of control.

Why Discs Need Movement to Stay Healthy

Unlike muscles, your intervertebral discs have no direct blood supply. They rely on diffusion—movement-driven fluid exchange—to get the nutrients they need to stay healthy.

This process is called tide flow. When you move, pressure within the disc changes, allowing fluids and nutrients to move in and waste products to move out.

But when you sit for hours:

The pressure stays constant
Nutrient exchange slows down
The proteoglycan content of the disc drops, reducing water retention
Over time, this contributes to disc degeneration, stiffness, and poor shock absorption³

This explains why sitting doesn’t just feel bad—it literally drains your discs of vitality.

The Role of the Nervous System: More Than Just Muscles

There’s a second layer to this problem: your nervous system.

When you sit still for too long:

Your multifidus, transversus abdominis, and diaphragm decrease their low-level postural firing
Your paraspinal muscles may brace reactively to protect the spine, leading to tension and fatigue
Joint position sense (proprioception) is diminished, confusing the brain’s spinal map⁴
The brain begins to associate sitting with discomfort, creating a learned pain response (central sensitization)

Think of it this way: your spine becomes the forgotten middle child—immobilized, under-stimulated, and increasingly sensitive.

And if you’ve had back pain in the past? Your system becomes even more vigilant.

Now, the brain treats sitting as a threat, and the pain that follows isn’t just from tissue stress—it’s from a protective, learned alarm response.

This is why some patients hurt even when imaging looks clean.
And why ergonomic upgrades help… but never fully solve the issue.

Why Movement Is Medicine for the Spine

Movement restores everything that sitting takes away:

It reactivates your segmental stabilizers (like the multifidus and rotatores)
It rehydrates the discs, increasing their height and resilience
It stimulates joint mechanoreceptors, which inhibit nociceptive (pain) signals via the gate control system
It reassures the brain that the spine is safe to move—and therefore safe to relax⁵

This doesn’t mean you need to do yoga every hour. It means you need movement variability, regular changes in position, and short bouts of targeted motion to break the pain loop.

What We Did to Help Marissa Sit Without Pain

When Marissa came in, she’d been told to sit with better posture. But that only made her tighten up more. She needed a different strategy—one that worked with her biology.

Here’s what we did in my Ashland chiropractic clinic:

Performed segmental spinal adjustments to restore motion and reduce joint tension
Taught her “disc hydration drills”—small movements like pelvic tilts, cat-cows, and decompression breathing throughout the day
Integrated neurodynamic flossing to reduce irritation of her dural and nerve tissues
Rebuilt diaphragmatic control, allowing her to sit upright with less effort and more natural stability
Coached her through a graded exposure plan to rebuild confidence with longer periods of sitting—without pain

Six weeks later, Marissa was back to working full days without distraction. She still used her lumbar support, but she no longer feared sitting. She had the tools—and the understanding—to manage her body instead of bracing against it.

If Sitting Hurts, Don’t Blame the Chair—Train the System

Pain with sitting isn’t a sign that your spine is weak, or your posture is bad.
It’s a sign your spine is undernourished, under-stimulated, and overprotected.

The solution isn’t to avoid sitting forever. It’s to reintroduce movement, reset your nervous system, and retrain your spinal support network.

If that sounds like a plan you’re ready for, I’d love to help.

Because your body isn’t breaking down.
It’s asking you to move differently—and more often.

References

Nachemson A. The lumbar spine: an orthopaedic challenge. Spine. 1976;1(1):59–71.
Adams MA, Roughley PJ. What is intervertebral disc degeneration, and what causes it? Spine. 2006;31(18):2151–2161.
Urban JP, McMullin JF. Swelling pressure of the intervertebral disc: influence of proteoglycan and collagen content. Biorheology. 1988;25(1-2): 118–119.
Brumagne S, et al. Role of paraspinal muscle spindles in lumbosacral position sense in individuals with and without low back pain. Spine. 2000;25(8):989–994.
Moseley GL. Reconceptualising pain according to modern pain science. Phys Ther Rev. 2007;12(3):169–178.