Why Your Back Pain Gets Worse
at Your Desk —And How to Fix It

I see it constantly in my Brussels practice: someone in their late 30s or 40s, working long hours in an office or at home, whose back pain has been quietly worsening for months or years. They've tried a new chair. They've watched YouTube videos on posture. They've spent €500 on a standing desk. The pain persists.

The frustrating thing is that they're not doing anything obviously wrong. They're not lifting heavy objects badly or sleeping on a terrible mattress. They're just… sitting. And therein lies the real problem.

It's not about bad posture

The most persistent myth in musculoskeletal health is that back pain comes from sitting in the "wrong" position — that if you could just hold your spine in the perfect neutral curve, the pain would stop. This isn't really how it works.

Research consistently shows that there is no single "correct" sitting posture, and that even people sitting in ergonomically optimal positions develop back pain when they sit for long enough. The reason is static loading.

Your back is composed of muscles, joints, ligaments, intervertebral discs, and nerves — a complex structure that is remarkably well-designed for movement but poorly designed for prolonged stillness. When you maintain any single position for an extended period, several things happen:

• The muscles holding that position progressively fatigue
• Blood flow to the discs and soft tissues decreases — discs are avascular and rely on movement to absorb nutrients
• The facet joints of the spine, designed to move through a range of positions, become loaded asymmetrically
• The hip flexors shorten and tighten, pulling the pelvis into an anterior tilt that increases lumbar compression
• The thoracic spine stiffens into flexion, creating a compensatory increase in lumbar lordosis

All of these changes accumulate over months and years of desk work. By the time you feel consistent pain, there's usually a meaningful amount of structural restriction that won't resolve on its own.

Why the pain often gets worse toward the end of the day

One of the most telling patterns I see is pain that builds through the day, peaks in the late afternoon or evening, and then eases overnight — only to return the following day. This is the classic signature of a postural/static loading problem.

In the morning, your discs are relatively hydrated and your muscles relatively fresh. As the day progresses, the cumulative effect of static loading and muscular fatigue builds up. The facet joints become progressively more restricted, the soft tissues tighter, and your pain receptors more sensitised. By late afternoon, minor movements that wouldn't cause discomfort in the morning become painful.

The overnight recovery you experience happens because lying down removes the compressive load from your spine and allows some degree of recovery — but without addressing the underlying restrictions, each day starts a little worse than the last.

The role of the hip flexors

This is the piece most people miss entirely. The iliopsoas — the deep hip flexor that connects your femur to your lumbar spine — is perhaps the single most important muscle in desk-related back pain, and it almost never gets addressed.

In a seated position, the iliopsoas is held in a shortened state for hours at a time. Over weeks and months, it adapts to this shortened length through a process called adaptive shortening. When you then stand up, this tight iliopsoas pulls the lumbar spine forward and downward, increasing compression on the lumbar joints and discs and placing the erector muscles of the lower back under constant strain.

This is why many desk workers feel a characteristic ache in the low back when standing, walking, or during exercise — not because those activities are harmful, but because the iliopsoas restriction is being provoked. Stretching the low back, as most people do, addresses the symptom but not the cause. The iliopsoas needs direct treatment.

What actually helps

Movement frequency matters more than posture

The single most evidence-supported intervention for desk-related back pain is simply moving more frequently. Getting up and moving for even 2–3 minutes every 45–60 minutes substantially reduces the cumulative load on your spine. Set a timer if necessary — the habit is more important than the specific exercises you do.

Hip flexor stretching

A standing lunge stretch held for 30–45 seconds per side, done two or three times daily, can make a significant difference over several weeks. It won't undo years of restriction on its own, but combined with treatment it maintains the gains between sessions.

Thoracic mobility work

A stiff thoracic spine forces the lumbar spine to compensate. Gentle thoracic extension exercises — arching backwards over the top of a chair, or lying over a foam roller — help restore mobility in the mid-back and reduce the compensatory load on the lower back.

Osteopathic treatment

The restrictions that accumulate over years of desk work — in the facet joints, the hip flexors, the thoracic spine, the sacroiliac joints — don't resolve fully with stretching alone. Hands-on treatment is significantly more effective at restoring joint mobility and releasing muscular tension than either exercise or ergonomic adjustments in isolation.

In my experience, most patients with established desk-related back pain see meaningful improvement within 3–5 sessions. The goal isn't just pain relief — it's restoring the mobility and function that allows the back to tolerate the demands of a sedentary working life.

What won't help (much)

I'll be direct about this because a lot of money gets spent on things with limited evidence:

• Expensive chairs — a supportive chair is worth having, but no chair eliminates the problem of prolonged stillness
• Standing desks used exclusively for standing — standing for 8 hours creates its own problems. The value is the ability to alternate
• Lumbar supports and cushions — these can provide short-term comfort but don't address the underlying restrictions
• Anti-inflammatory medication long-term — manages pain but doesn't treat the mechanical cause