Why you feel lower back pain when sitting and the best ways to relieve it

• Lower back pain when sitting is common, as this position puts more pressure on your spine than standing up or lying down.
• Lower back pain when sitting can also be exacerbated by poor posture, sciatica, a herniated disc, or spinal problems.
• To relieve lower back pain when sitting, you can adopt good posture, try a few key stretching exercises, and make sure you're getting up every 20 minutes or so.

If you experience lower back pain while you're sitting, you're not alone. About 75% to 85% of Americans experience back pain at some point in their lives - and it has been estimated that lower back pain is the most common cause of disability worldwide.

Here's what you need to know about the major causes of lower back pain and how to fix it.

Causes of lower back pain when sitting

Your spine, also called your backbone or vertebral column, has 26 vertebrae (bones) that are separated by soft, spongy discs that serve as shock absorbers. The portion in your lower back area, called the lumbar spine, contains five vertebrae.

"Sitting puts the lumbar discs and other structures in your back under more pressure than other positions, such as standing or lying down," says Jeremy James, DC, CSCS, a chiropractor who specializes in chronic back pain and founder of FITFOREVER.

Sitting for long periods of time exacerbates this, he explains, because of a condition called "creep," where the ligaments and discs in your back deform over time when you're sitting. Once creep sets in, those tissues are in a compromised state that can lead to pain.

Even if you have good posture, you may experience lower back pain if you remain seated for long periods of time because of the pressure it puts on your back muscles and spinal discs. Poor posture can make lower back pain even worse - stretching ligaments, straining discs, and even damaging your spinal structures.

These are some of the other possible causes of lower back pain:

• Sciatica: Pain in your sciatic nerve can extend from your spine to the back of your legs, usually on one side of your body. It may be a dull ache or feel like an electric shock. Among the causes may be a herniated disc, spinal stenosis, or a pelvic injury.
• Herniated disc: Also called a slipped or ruptured disc, this happens when the soft center of a disc leaks through a tear in the disc's outer layer. It can be the result of aging, lifting something the wrong way, a fall, or a repetitive motion injury. A herniated disc can cause pain, numbness, or tingling in your buttocks and legs, but many people don't experience any symptoms.
• Degenerative spine disease: Although it's not really a disease, this occurs when the discs between your vertebrae wear down. The pain may worsen when you're sitting and can extend to your legs and feet. Degenerative disc disease may be caused by aging, disc tears due to sports and other physical activities, or an injury.
• Spinal stenosis: This is a condition that usually occurs gradually as your spine narrows and compresses your spinal cord, putting pressure on your nerves. It is most often caused by aging, or in younger people may be caused by an injury, arthritis, or scoliosis. The symptoms may include pain, numbness, or weakness in your lower back.

Best sitting position for lower back pain

For starters, lower back pain may be alleviated by changing your posture when you sit.

"The best position is to sit tall, with your chest up and shoulders down and back," James says. "There should be a slight curve in your low back. Try to keep your head over your shoulders and not leaning forward."

A small 2006 study in Scotland using magnetic resonance imaging (MRI) found that sitting upright at a 90-degree angle put unnecessary strain on the backs of 22 healthy participants. Slouching reduced the height of their spinal discs, which could lead to wear and tear. The researchers concluded that the ideal sitting position is reclining backward at a 135-degree angle with your feet on the floor.

How to relieve lower back pain when sitting

The best strategy for preventing lower back pain when sitting, James says, is to get up and move around every 20 minutes, which is the length of time it usually takes for the creep process to set in.

If you're unable to do this, James recommends changing positions as you sit, such as crossing one leg over the other or leaning to one side. "This will change the tissues in your back that are under load, which can prevent pain and delay the creep process," he says.

You can also help relieve your lower back pain with the following:

Stretching. Doing stretching exercises that put your body in positions opposite of the sitting position may also help, James says. Researchers have found that just 15 minutes of daily stretching exercises can help increase your flexibility and reduce your lower back pain.

For one example, the American Academy of Family Physicians (AAFP) recommends laying on your back with your knees bent and slowly raising your left knee to your chest, holding it there for five seconds. Do the same with your right knee. Repeat this exercise 10 times for each leg.

Over-the-counter medications. Analgesics like aspirin or Tylenol (acetaminophen), or non-steroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen) or Aleve (naproxen) may help relieve pain and inflammation.

Ice or heat. An ice pack or water bottle filled with cold water can help relieve your lower back pain, according to the AAFP. A heating pad or hot water bottle can also help relax your muscles and reduce spasms. The AAFP recommends applying heat to your lower back for 20 to 30 minutes at a time.

Practicing a healthy lifestyle. People who are overweight, lack regular exercise, or smoke are more likely to have back pain, according to the National Institutes of Health. Losing weight, exercising regularly, and stopping smoking may help provide relief.

When to see a doctor

You should always see a doctor for lower back pain that lasts more than a few days, James says. He advises looking out for the following symptoms that may be red flags:

• Pain that extends down your leg
• Numbness in the lower part of your body
• Pain that doesn't change when you change your body position
• Pain that wakes you up at night
• Fever
• Nausea

Insider's takeaway

"Our bodies were made to move, not sit all day," James says. "Sitting for prolonged periods of time is not a natural healthy thing for our bodies." To help prevent lower back pain, it's best to avoid sitting for more than 20 minutes at a time and to move your body regularly.

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• Exercises that help you deal with chronic pain while working from home
• 4 benefits of Hatha yoga and how it can improve your physical and mental health
• The health benefits of foam rolling and how to add it to your workout routine
• Aspirin vs. ibuprofen: The key differences and which one you should take
• 5 major types of painkillers and how to take each safely