Why your favourite armchair position may be aggravating lower back pain over time

The telly is on, the mug is warm, your body finds the same soft groove in the armchair it always does. You shift once, maybe twice, then sink into that familiar slouch that feels like exhaling. Ten minutes in, it’s bliss. Forty minutes later, you stand up a bit more slowly than you used to. There’s a tight band across your lower back, a dull ache at the base of the spine. You tell yourself it’s age, or “just the way I slept”. You sit again tomorrow in exactly the same way.

Your favourite sitting position often feels good precisely because it lets your body switch off and stop working. The catch is that your spine doesn’t get a vote. The way most of us curl into sofas and armchairs quietly loads the lower back for long stretches, nudging discs, joints and muscles into shapes they tolerate for a while – until they don’t. The pain rarely shouts at first. It whispers, then lingers, then arrives faster each evening.

What your armchair is really doing to your lower back

A spine in its happy place has gentle curves: a small inward curve in the lower back, a smooth outward curve in the upper back, and your head balanced roughly over your shoulders. Many armchairs work against that shape. The seat is deep, the back is soft, the cushion slides. Your hips tip backwards, your lower back rounds, your head drifts forward towards the screen. It feels “relaxed” because your muscles switch off and the chair holds you – but the load shifts onto the structures at the base of your spine.

Picture someone who sits every evening with feet tucked under them, slumped to one side into the arm of the chair. Their pelvis is tilted, one hip higher than the other, their lower back curved like a C. For ten minutes, it’s cosy. Over months, that uneven pressure asks one side of the lumbar spine to carry more than its share. Muscles on one side work harder to keep you from toppling. Joints, discs and ligaments adapt to the asymmetry. Then one day, they bend to grab a dropped remote and feel a sharp pull that “comes out of nowhere”.

Time is as important as position. Lower back structures tolerate a bit of flexion, a bit of twist, a bit of slump. Problems build when you stack them for hours in the same direction every night. The tissues that hold your vertebrae together are viscoelastic – they creep under steady load. That slow creep can irritate joints, edge discs backwards, fatigue the deep muscles that quietly stabilise you. The result is the familiar pattern: you feel worst when you get up after a long sit, then ease off with gentle movement, only for the stiffness to return when you settle again.

The positions that quietly turn comfort into strain

You don’t need a degree in biomechanics to spot the usual suspects. Certain “ah, that’s better” postures share the same themes: rounded lower backs, twisted trunks, unsupported heads, feet dangling. Each offers instant relief at a cost that’s easy to underestimate when you’re tired.

Common armchair habits that can wind up your lower back:

• The deep slump: bottom slid forwards, shoulders low, head propped on the backrest. Your pelvis rolls back, flattening and then reversing your natural lower-back curve.
• The sideways curl: leaning into one armrest with legs hooked to the opposite side. Your spine bends and rotates, loading one set of joints more than the other.
• The feet‑off‑floor lounge: legs stretched on a coffee table or pouffe with no support under the knees. Your hamstrings pull on the pelvis, tilting it and rounding your lower back further.
• The half‑twist: body facing the TV while your hips are still turned towards a side table or conversation. The twist feels minimal, but your lower spine is holding that rotation the whole time.

Individually, none of these positions is “forbidden”. The issue is repetition. The position you melt into every night becomes the shape your tissues learn as normal. Muscles that should share the load fall asleep. Others stay braced, becoming tight and tender. Your nervous system starts to associate long sitting with discomfort, so it becomes easier to trigger pain with smaller provocation – an extra episode, a longer film, a rainy weekend on the sofa.

What makes this more subtle is that many chairs are sold on softness, not support. Deep cushions that swallow your hips, backs that recline without supporting the lumbar curve, armrests that encourage leaning – they all hide the work your lower back is quietly doing. The first sign is often not a dramatic injury but a creeping rule you make for yourself: “I just can’t sit for long any more”.

How to keep your armchair – and stop feeding the pain

You don’t need to banish your armchair or sit bolt upright in a dining chair all evening. Small, boring adjustments done consistently often change the story more than heroic stretches once in a blue moon. Think less “perfect posture” and more “varied, supported positions that your lower back can live with”.

A simple checklist when you next sit down:

• Hips, not tailbone, against the backrest: shuffle your bottom backwards so your weight is on your sitting bones, not on the soft tissues of your lower spine.
• Support the curve: place a small cushion, rolled towel or lumbar pillow in the gap between the chair back and your lower back so you keep a gentle inward curve, not a rounded C‑shape.
• Feet grounded: if your feet don’t reach the floor comfortably, use a footrest or firm cushion so your thighs are roughly horizontal and your knees are not dragging your pelvis.
• Head over chest, not in front of it: if you have to push your head forwards to see the screen, move the screen or adjust your chair rather than your neck.

When you’re watching something longer – a match, a film, a few episodes in a row – set movement as a non‑negotiable part of the plan. Every 20–30 minutes, change something: stand up, walk to the kitchen, do a slow back extension by placing your hands on your hips and gently arching backwards within comfort. It doesn’t need to be a workout. The goal is to break the “creep” – that slow, sustained load that irritates the lower back when you stay in one shape too long.

It’s also worth rotating your “favourite” position. If you always lean into the right armrest, occasionally swap ends or sit more centrally with both feet flat. If you love feet up on a stool, try placing a pillow under your knees so your lower back doesn’t flatten as much. Think of it as giving your tissues different jobs so no single area gets overworked.

“We don’t ask people to perch like statues,” says one musculoskeletal physio. “We ask them to give their back three or four different shapes each hour, instead of just one.”

• Shuffle back into the chair so your hips are supported.
• Add a small lumbar cushion where your lower back naturally curves.
• Keep feet supported so your legs aren’t dragging your pelvis.
• Change position or stand briefly at least once an episode.
• Favour variety over a single “perfect” posture.

When to see someone – and what that really means

Not every ache from the armchair is sinister. Many people notice improvement within a few weeks when they tweak how and how long they sit. But persistent, worsening, or spreading pain deserves a proper look, especially if it starts to pinch down a leg, wake you at night, or limit what you can do in the day. You don’t get a medal for waiting until it’s unbearable.

Red flags that mean you should seek urgent medical advice include: difficulty controlling your bladder or bowels, numbness around the groin or saddle area, severe weakness in a leg, or back pain linked to fever, unexplained weight loss, or a significant fall. These signs are rare but important. For the vast majority, what’s driving the discomfort is a blend of posture, deconditioning and lifestyle patterns, not something that demands immediate scans or surgery.

Seeing a GP, physiotherapist or other qualified clinician earlier rather than later is less about alarming findings and more about getting tailored guidance. They can help you distinguish “irritated but safe to move” from “needs more investigation”, and suggest specific exercises that wake up the deep stabilising muscles your armchair has let go quiet. Often, a plan that mixes movement, strength work, and smarter sitting beats a new gadget or miracle cushion.

If your armchair is part of a wider pattern – long commutes, desk work, little movement in the day – the conversation may widen too. That’s not a judgement. It’s an invitation to spot all the places your lower back is doing extra shifts so you can share the load. You’re not trying to live pain‑free by never slouching again; you’re trying to make slouching just one position among many, not the only one your body knows.

Key point	Detail	Why it matters
Familiar slouch = sustained load	Favourite soft positions often round or twist the lower back for long periods.	Explains why pain can build even when you feel “relaxed” at the time.
Time in position counts	The problem is hours in one shape, not a single bad sit.	Shifts focus from perfection to regular small changes and breaks.
Simple supports help	Cushions, footrests and position changes can ease strain.	Lets you keep your armchair while reducing aggravation.

FAQ:

• Is slouching always bad for my back? Not in short bursts. Your spine is built to move and bend. Trouble tends to arise when you stay in the same slumped position for long stretches, night after night, without giving your back other shapes and some support.
• Do I need to buy an expensive “ergonomic” chair? Not necessarily. Many people get relief by adjusting the chair they already own – shuffling back, adding a small lumbar cushion, supporting their feet, and breaking up sitting time with short movement.
• Why does my back hurt most when I stand up after sitting? Long, static sitting can temporarily stiffen joints and fatigue supporting muscles. When you first stand, those structures have to work again, so they complain. Gentle regular movement usually improves this “start‑up” pain.
• Can exercises really offset my armchair habits? They can help a lot. Strengthening your core and hip muscles, and keeping your spine mobile, makes you more resilient to less‑than‑ideal sitting. But it works best alongside, not instead of, adjusting how you use your chair.
• When should I worry about lower back pain? If pain is severe, getting worse, associated with leg weakness, numbness, bladder or bowel changes, or feels linked to illness or a fall, seek medical advice urgently. Otherwise, if it lingers beyond a few weeks or keeps returning, it’s sensible to get it assessed rather than simply living with it.