Your sciatic nerve is most likely hurting because something is pressing on it or irritating it where it exits your lower spine. The sciatic nerve is the longest nerve in your body, formed from nerve roots in the lower back that merge and run down through your buttock, the back of your thigh, and into your lower leg. When one of those roots gets compressed or inflamed, the pain can radiate along that entire path. The cause is usually a structural problem in your spine, but not always.
The Most Common Cause: A Disc Problem
Between each bone in your spine sits a soft, gel-filled disc that acts as a shock absorber. If the outer layer of a disc weakens or tears, some of that inner gel can bulge or leak out and press directly on a nearby nerve root. This is a herniated disc, and it’s the single most frequent reason people develop sciatica.
The pain isn’t purely mechanical, though. When disc material herniates, it releases inflammatory chemicals that irritate the nerve root even beyond what the physical pressure alone would cause. This is why two people with similar-looking disc bulges on an MRI can have wildly different pain levels. The combination of compression and inflammation is what makes sciatica so intense for some people: sharp, burning pain that shoots down the leg, sometimes with numbness, tingling, or a feeling that the affected leg is heavy and hard to control.
Spinal Stenosis and Aging
If you’re over 50 and dealing with sciatica, spinal stenosis may be the culprit. Over time, the spinal canal (the bony tunnel your nerves pass through) can gradually narrow. This happens through a few overlapping processes: arthritis causes small bone spurs to grow on the vertebrae, discs lose height and may bulge, and the ligaments that hold the spine together thicken and stiffen. All of these changes eat into the space your nerves need, and the result is pain or cramping in one or both legs, especially when standing or walking.
Stenosis tends to develop slowly rather than striking suddenly. Many people notice that leaning forward or sitting provides relief because those positions temporarily open up the spinal canal.
Piriformis Syndrome: Pain Without a Spine Problem
Not all sciatic pain originates in the spine. The piriformis is a small muscle deep in your buttock that runs from the base of the spine to the top of the thigh bone. The sciatic nerve passes right next to it, and in some people, directly through it. When the piriformis goes into spasm, it can squeeze the sciatic nerve and produce the same shooting pain, tingling, and numbness you’d get from a disc herniation.
There are some clues that point toward piriformis syndrome rather than a spinal issue. People with piriformis syndrome are less likely to have lower back pain. Their pain tends to flare with hip movements and prolonged sitting, rather than when raising the leg while lying flat. If your pain is centered deep in your buttock and worsens when you cross your legs or rotate your hip, the piriformis is worth investigating.
Pregnancy Can Trigger Sciatica Too
Sciatica during pregnancy has its own set of causes. Your body produces a hormone called relaxin that loosens tendons and ligaments throughout your joints to prepare for delivery. That loosening can destabilize the structures around your lower spine. At the same time, your growing belly shifts your center of gravity forward, which deepens the curve of your lower back as your body tries to redistribute the weight. Both changes can put new pressure on the sciatic nerve.
Who Gets Sciatica More Often
Certain jobs carry a significantly higher risk. Research on occupational risk factors found that blue-collar workers in industrial settings and motor vehicle drivers had the highest rates of hospitalization for herniated discs and sciatica, while people in professional or desk-based jobs had the lowest. For men, the type of work mattered most. For women, the self-assessed physical strenuousness of the job was the strongest predictor, regardless of occupation category.
Beyond occupation, other factors that increase your risk include carrying excess body weight (which adds load to the spine), sitting for long stretches without movement, diabetes (which can damage nerves over time), and a previous back injury. Age plays a role too, since discs naturally lose water content and become less flexible starting in your 30s.
What Recovery Typically Looks Like
The encouraging news is that most sciatica resolves without surgery. About 50% of people see meaningful improvement within just ten days, and roughly 60% of cases improve within three months using only conservative pain management like over-the-counter anti-inflammatory medications, gentle movement, and time. The body can gradually reabsorb herniated disc material, and inflammation settles on its own in many cases.
Recovery doesn’t always follow a straight line. You might have a good week followed by a flare-up, especially if you sit too long or do something that irritates the nerve again. The general trajectory matters more than any single day. Signs that you’re heading in the right direction include pain that centralizes (moves from the leg back toward the lower back), returning sensation in numb areas, and being able to sit or stand for longer periods without symptoms.
Physical therapy is one of the most effective tools for both relieving current symptoms and preventing recurrence. A therapist can identify whether your pain responds better to extension-based exercises (arching the back) or flexion-based ones (rounding forward), which varies depending on the underlying cause. Core strengthening, nerve gliding exercises, and postural corrections all help reduce the load on the nerve over time.
Symptoms That Need Emergency Attention
In rare cases, a large disc herniation or other spinal problem can compress not just one nerve root but a whole bundle of nerves at the base of the spine called the cauda equina. This is a surgical emergency. The warning signs are distinct from ordinary sciatica: sudden loss of bladder or bowel control (either inability to go or inability to stop), numbness in the inner thighs, groin, or buttocks (sometimes called “saddle” numbness), and rapidly worsening weakness in one or both legs. If these symptoms appear, especially suddenly, you need an emergency room. Surgery within 24 to 48 hours gives the best chance of preventing permanent nerve damage.
Outside of that emergency scenario, sciatica that hasn’t improved after six to eight weeks of conservative treatment, pain that’s getting progressively worse rather than better, or significant leg weakness that makes it hard to walk or lift your foot are all reasons to pursue further evaluation, which typically involves imaging like an MRI to see exactly what’s going on inside the spine.