Lower back pain can be caused by a variety of reasons, including posture, a weak core, and some underlying medical conditions.

Lower back pain is defined as pain in the vertebrae designated L1 through L5. These comprise the part of the spine that curves inward at the base.

A common reason your back may hurt is from bad posture while seated. Sitting in a slouched or hunched position can put strain on the discs: fluid-filled cushions that protect the vertebrae from rubbing against each other. This may be worsened by an underlying medical condition.

Not all back pain is the same, and there are many possible causes.

Sciatica

Sciatica refers to pain in the sciatic nerve, which runs down the base of the spine into the back of your legs. It can be caused by various conditions.

This occurs when the sciatic nerve is compressed, often at the level of the spine. When you sit, you tense the sciatic nerve, stretching it out.

The pain can range from a dull aching sensation to a burning sensation. Sitting for long periods can exacerbate the condition, but it typically only affects one side.

Herniated disc

You may experience pain in your lower back if you have a herniated disc, which is when pressure on your disc causes it to deviate from its shape. This puts strain on the spinal cord and nerves in the area, causing pain and even numbness.

Older people often get a herniated disc as a natural part of the aging process. It can also occur due to:

  • a fall
  • lifting something incorrectly
  • repetitive motion injury

Muscle strain

A muscle strain in the lower back — also known as mechanical back strain — can occur for a variety of reasons, such as lifting something heavy.

If you have a muscle strain, you may experience pain that extends down into your buttocks but not your legs. A strain can also cause your back to become stiff, making it difficult to move.

While most people recover from a strain within one month, it can also become an ongoing issue if it’s caused by an improper sitting posture.

Degenerative disc disease

Degenerative disc disease occurs when the discs between the bones in the lower spine are damaged.

Discs degenerate in older people, and injuries can cause the annulus fibrosus to tear. The annulus fibrosus is what holds the nucleus pulposus, the soft center of each disc, in place.

Although some people who have degenerative disc disease don’t have symptoms at all, the pain can be quite severe in the lower back, buttocks, and thighs, and it may get worse when you bend or sit.

Spinal stenosis

The bones in the spine each have a hole in the middle that form a tube through which the spinal cord runs. This connects the nerves throughout your body to your brain.

When that tube isn’t wide enough, the cord gets squeezed and can cause pain, weakness, or numbness. This is called spinal stenosis.

Spinal stenosis can result from an injury, arthritis, a tumor, or an infection. Some people are born with a narrow spinal canal.

Posture

Bad posture while either sitting or standing can contribute to lower back pain. Slouching forward too much or leaning too far back can create problems.

Even if your back pain isn’t caused by poor posture, it can be made worse by it.

Weak core muscles

Your core muscles include those located on your sides, back, hips, abdomen, and buttocks. If these are weak, they may not be supporting your spine well enough, leading to pain.

Stretching and aerobic exercise can go a long way toward helping strengthen your core. This should lessen your discomfort by reducing the degree of strain on your back.

Other medical conditions

Sometimes, your lower back may hurt due to another condition. This can include kidney stones, a gallbladder issue, and in rare cases, a tumor or problem with your main abdominal artery.

Sitting with your back rounded forward, slumped to one side, or leaning too far back can put stress on parts of your spine for an extended period. This can lead to pain, as well as other issues.

To help you sit straighter, position your body along an imaginary straight line extending the length of your back, out of your head, and up to the ceiling. Keep your shoulders level and don’t let your pelvis rotate forward. Doing so causes a curve in your lower back.

If you sit up perfectly straight, you’ll feel the small of your back stretch and lengthen.

In addition to improving your posture when sitting, try these at-home remedies for lower back pain:

  • Change your position. Consider a standing desk or one that’s ergonomically designed to help you maintain good posture by allowing you to adjust the height of your monitor.
  • Apply ice. Cold helps reduce inflammation that may be affecting your back. Leave the ice pack on for about 20 minutes, and then remove it. You can do this every hour or so.
  • Use a heating pad. After any inflammation is under control (about 24 hours or so), many people find heat soothing. It also promotes healing by bringing blood to your back.
  • Take over-the-counter medication. Pain relievers like nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce discomfort and swelling.
  • Use a support. Placing a rolled-up towel or special lumbar pillow at the base of your spine while sitting will help you remember to sit up straight and provide you with some stability.
  • Get a massage. This can help loosen and relax tight muscles.
  • Consider yoga. Yoga is known for its ability to stretch and strengthen the body. Many programs allow for modification of the poses as needed.

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Several exercises can help strengthen your lower back. Exercise can also help you lose excess weight, which some evidence suggests may help improve back pain. However, it is essential to note that research findings are mixed.

The plank

  1. Get into pushup position with your forearms on the ground.
  2. Keeping your elbows in line with your shoulders, push up onto your forearms and toes, keeping your back straight and your elbows on the ground.
  3. Hold for a few seconds, and then lower yourself to the floor.

The bird dog

  1. Get on your hands and knees, keeping your back straight.
  2. Extend one leg and the opposite arm straight out.
  3. Hold for five seconds, and then rest.
  4. Alternate with the other leg and arm.

The arch

  1. Lie on your back with your arms by your sides.
  2. Gradually lift your hips using your back, buttocks, and abdominal muscles.
  3. Hold for five seconds, and then relax.

Doctors may recommend the following treatments for lower back pain:

  • physical therapy, which helps build up muscle strength to support your back
  • nerve blockers and steroid injections for pain relief
  • acupuncture and laser therapy, which may relieve pain without surgery
  • medications, such as muscle relaxers, antidepressants, and other analgesics

Surgery is usually considered a last resort, and opioid medications aren’t viable long-term solutions.

While lower back pain usually clears up with exercise and better sitting posture, you should see a doctor if:

  • the pain is persistent and doesn’t seem to be getting better
  • you have tingling or numbness in your back or legs
  • you have a fever
  • you’re unusually weak
  • you lose bladder or bowel function
  • you’re losing weight

These symptoms can signal a serious condition that should be addressed right away.

Lower back pain is a common problem, and while it’s likely to worsen as we age, there are steps we can take to protect and strengthen our backs.

Being mindful of maintaining a correct sitting position, keeping core muscles toned to support the spine, and seeing a doctor when the problem is severe or persistent will help keep your back in its best possible shape.