Earlier this year, we spoke with Dr. Stuart McGill, one of the world’s leading researchers on spinal mechanics and low back health to better understand what triggers back pain.

Many of you responded, asking for Dr. McGill to delve deeper into sciatica, a specific type of low back pain that commonly plagues older adults. Here he is again, sharing sound advice — and a few pain-relieving exercises to try.

Q&A with Dr. Stuart McGill

Q: What causes sciatica?

A: Sciatica is the result of irritation of the sciatic nerve which originates from the two lower lumbar joints in the spine. The majority of sciatic nerve pain is triggered by a bulging disc. Our vertebrae are cushioned by spinal discs that act as shock absorbers and allow movement.

But these discs can become overloaded and damaged from repeated bending with compression, such as lifting with poor posture. Over time, these stresses can cause a disc bulge that puts pressure on the sciatic nerve root, causing the familiar pain in the buttocks, down the posterior thigh, and even into the foot and toes. For older adults, sciatica pain may be caused by a disc issue, but it could also be because of arthritic changes. As we age, the joints and ligaments in the back of our spine grow thicker. This leaves less space in the canals that our sciatic nerves run through causing irritation, leading to sciatica.

Q: What is stenosis? How it is tied to sciatica?

A: Stenosis is common in older adults. It’s a subcategory of sciatica that’s caused by arthritis and aging. Stenosis means “the narrowing of.”

When you have spinal stenosis, the spinal canal that houses your spinal cord and nerve roots becomes more narrow, and begins to pinch and irritate the sciatic nerve roots. If you have arthritis, inflamed joints or the presence of bone spurs, rubbing on the sciatic nerve root is what causes the common sciatica symptom of pain running down your buttocks and the backs of your thighs. If you have disc bulges, they can also push into the spinal canal, leading to the diagnosis of stenosis.

Q: How do you determine if sciatica is caused by a disc or arthritic issue?

A: If you have disc bulges or disc imperfections, sitting can cause the disc bulge to push posteriorly onto the sciatic nerve more than standing. You might also experience painful pins and needles in your right foot. But you may find that the pain goes away when you stand up. If you have this pain pattern, lay down on your stomach for about three minutes with your palms under your forehead. If the sciatica goes away when you stand up, the pain is likely due to a disc bulge.

For people with more of an arthritic type of sciatica, it’s the opposite. Sitting for half an hour may provide relief, while walking or standing for 15 minutes exacerbates the pain.

What’s most important, in this case and in all cases, is to nail down the nature of the specific pain trigger and to use the right clinical tools to address the discomfort. I encourage those with sciatica to try the self-assessment in my book Back Mechanic to better understand what’s triggering their sciatica pain.

Once you understand your specific pain trigger, you’ll be able to target the root cause of the pain rather than just the symptoms.

Q: Is there a cure for sciatica? Are there specific exercises that can help relieve sciatica pain?

A: It depends on what’s triggering the pain. If you experience pain when you sit down, but then the pain goes away when you stand up and walk around, practicing good spinal hygiene can address this type of pain. This means bending through the hips rather than through the spine.

Also, doing the “Big 3” exercises [the modified curl-up, side bridge and bird dog] and going for repeated interval walks throughout the day will usually help. If you start to feel pain when you’re walking, stop and do a park bench decompression.

In half of people, the pain will go away and you’ll be able to continue walking for another 5-10 minutes. The key is to keep up your walking intervals and pause to do the park bench decompression until you’re able to walk longer distances. Slowly over time, the discs will toughen and the disc bulge will go away practicing these principles of spine hygiene.

If the sciatica pain is more arthritic, going for a walk may make the pain worse. With these types of patients, achieving a proper pelvic tilt and doing nerve flossing exercises are what’s most helpful for targeting and addressing the pain trigger.

Q: What’s nerve flossing? How do you do it? What’s the benefit?

A: Nerve flossing is a simple technique used to ease neural tension in the body. When you move, your nerves aren’t static. They move down the middle of your spine, and they exit through little holes in the bone called foramens to travel to different parts of the body.

If you have stenosis or narrowing of those holes, friction occurs on the nerve root as it slides. Nerve flossing can reduce the friction and thus nerve sensitivity pathway. This is important for good nerve health because the movement keeps the nerves moving without friction. As with all therapies, flossing will also make some people more sensitive. If that happens to you, stop flossing immediately. Then try again in another month after practicing good spine hygiene to see if you have created the foundation for therapy to be effective.

How to Practice Nerve Flossing

To practice nerve flossing, find a pain-free sitting posture. Open your hips and achieve a neutral spine curve. Make sure you sit on a chair or on the edge of a table where there’s enough room to swing your legs freely.

Extend the knee (pulling the foot up) and neck at the same time, creating a fluid and coordinated movement. Then perform the opposite motion. Swing your leg underneath you, point your toes and flex your neck downwards. This flosses the sciatic nerve through the foramen which can desensitize the pain (or as noted can make it more sensitive).

Do 10 repetitions on each leg. See how you feel the next day. If you’re still in pain, your body might not be ready yet and you may have to let some inflammation settle down or do some further work to reduce the disc bulge. But if you feel better, try nerve flossing again the following day.

Q: Is stretching the hamstrings an effective solution for relieving sciatic nerve pain?

A: What many people perceive as hamstring tension is actually tight nerves. Unfortunately you can’t just stretch away nerve pain. You can help nerve pain away by performing the nerve flossing exercise but if you stretch an already-painful sciatic nerve root, it more often will remain painful.

Instead, lay down on your stomach for about three minutes with your palms under your forehead to see if that helps desensitize the nerve roots. Doing the “Big 3” exercises and going for short walking intervals throughout the day may also help ease a tight sciatic nerve root.

The length of your walking intervals will depend on your pain trigger. If your pain is due to a disc bulge, try walking three times a day, for about 15 minutes each time. But, if your pain is more arthritic, try taking a short walk every hour, even if it’s just to the end of your driveway and back.

Get the Book

Dr. McGill has helped thousands of people reclaim their lives with his evidence-based guide, Back Mechanic (available online at backfitpro.com). Back Mechanic guides you through a self-assessment to identify your specific pain triggers, then shows you step-by-step exercises to address the pain and avoid roadblocks to recovery.