Why Does Sciatica Get Worse When You Sit Down?
If a long car journey, a desk day, or even sitting through a film leaves you with a burning ache running down the back of one leg, and standing up brings a few seconds of relief, you're not imagining it. That specific pattern, worse the longer you sit, briefly better the moment you stand, is one of the clearest signs of sciatica there is.
Here's the short answer: sitting narrows the space in your lower spine, especially when slouched, and that can compress the sciatic nerve right where it's already irritated. That's why standing, walking, or even just shifting position can bring quick, if temporary, relief.
So sciatica getting worse when you sit isn't bad luck, and it isn't something you just have to put up with. It's a nerve telling you it doesn't like a particular position, and once you know why, there's a lot you can do about it this week.
The usual suspects
Disc bulge or herniation. The most common cause of true sciatica. A disc presses on or irritates the nerve root as it leaves the spine, and sitting, especially slouched or leaning forward, tends to load that area the most.
Piriformis irritation. The piriformis muscle sits deep in the buttock, close to the sciatic nerve. When it tightens up, it can squeeze the nerve in a way that feels almost identical to a disc problem, especially after long periods sitting.
Spinal stenosis. A narrowing of the space around the nerves, more common from your 50s onward. It tends to ease with sitting or bending forward, which is a useful clue when sitting itself isn't the trigger.
Nerve root irritation without a major structural issue. Sometimes there's no significant finding on a scan at all, just a nerve that's become sensitised and needs calming down before being gradually reloaded.
The mistake almost everyone makes
Sitting very still and waiting it out. When sciatica flares, the instinct is to avoid anything that provokes it and sit tight until it passes. But prolonged stillness, especially sitting, is often exactly what keeps compressing the nerve. A week spent barely moving tends to leave sciatica just as irritable as one spent overdoing it, just for a different reason.
Three things to try this week
Break sitting up every 20 to 30 minutes. Stand, walk to the kettle, roll your shoulders, anything that takes sustained load off the lower back and the nerve.
Sit tall rather than slouched. A rolled towel or small cushion in the small of your back keeps the lower spine in a better position and takes pressure off the nerve.
Try gentle, regular walking before stretching. Short walks tend to calm true sciatica down more reliably than aggressive hamstring stretches, which can aggravate an already irritated nerve.
When to get it looked at
Most sciatica settles over several weeks with the right loading and movement changes, but it's worth getting assessed if the pain is severe, spreading below the knee, or if you notice numbness, tingling, or weakness in the leg or foot. Any loss of bladder or bowel control, or numbness around the saddle area, needs same-day medical attention, so go straight to A&E rather than waiting for an appointment. At TAP we start by working out exactly where the irritation is coming from, disc, piriformis, or stenosis, because the right loading plan is different for each one, then build you back up in a way that respects the nerve rather than fighting it.
Quick answers
Is it sciatica or just a tight hamstring? A tight hamstring usually stays in the back of the thigh. Sciatica typically travels further, often past the knee into the calf or foot, and sometimes brings pins and needles or numbness with it.
Do I need a scan? Not usually to begin with. A clinical assessment normally tells us enough to identify the likely source and start the right treatment, and scans are kept for cases that aren't improving as expected or where something more urgent needs ruling out.
Will it come back? It can, if the same postures and loads return unchanged. That's why the plan includes changing how you sit and move day to day, not just calming the current flare.
Want the full picture on your specific sciatica? Visit our sciatica page for the conditions we treat, what assessment looks like, and honest recovery timelines.
Tired of a nerve that flares every time you sit down? We can usually see you the same week at Warwick or Stratford-upon-Avon, no GP referral needed. Book your assessment or learn about physiotherapy in Warwick and physiotherapy in Stratford-upon-Avon.