What is lower back pain?

Lower back pain¹ is any pain that occurs below the midpoint of the back (most commonly around the level of the hips).

Lower back pain can occur when any of the structures in the back (joints, bones, muscles, ligaments, nerves, the spinal column and cord, and discs between the vertebrae) aren’t fitting together or moving as they should. This can be the result of an injury or strain, strenuous exercise, or normal wear and tear.

Lower back pain often feels like a muscle ache, but may also feature shooting or stabbing pain. Sometimes, this pain may seem to travel down one or both legs. It may worsen when in certain positions or with certain types of movement.

Generally, back pain can be characterized as either acute or chronic.

Most cases of lower back pain are acute. Acute back pain, most commonly caused by an injury, lasts for a few days to a few weeks. While medical treatment may be required, most cases of acute lower back pain resolve on their own with adequate rest and self-care.

Chronic back pain is defined as back pain that lasts for at least 12 weeks, even after the initial injury or underlying cause of the pain has been treated. Additional medical or surgical treatment may be required to alleviate chronic lower back pain. In some cases, however, the cause of the pain is unclear. In these cases, lower back pain can persist despite treatment.

How common is lower back pain?

Medical experts believe that at least 60–70%² of people experience low back pain during their lifetimes. In any given year, at least 5%³ of adults will experience it.

While lower back pain is most common in people between 35 and 55⁴ years old, the prevalence among children and adolescents is rising.

Lower back pain is one of the leading causes of activity limitation and missed work worldwide and the most common cause of disability among young adults. In the United States alone, lower back pain causes roughly 149 million workdays to be lost each year.

This is, in part, due to the widespread prevalence of back pain. It can also be attributed to the fact that sitting for long periods of time (which many workers are required to do at their jobs) puts tension on the spine⁵—particularly in the lower back—and compresses the spinal discs, contributing to their premature degeneration.

Lower back pain causes

Most lower back pain is caused by structural problems in the back. Different issues, however, can occur for different reasons: some are the result of congenital problems, while others may arise after an injury.

Some of the most common causes⁶ of lower back pain include:

• Everyday injuries: These sprains, strains, or spasms—sometimes caused by heavy lifting, strenuous exercise, or moving too quickly—can be quite painful. However, they usually don’t require extensive treatment and will frequently heal on their own with rest.
• Traumatic injury: This may be caused by a car accident, a workplace accident, physical activity/sports, or a fall. These are often more severe than everyday injuries and, as a result, may require more extensive treatment before the patient begins to recover.
• Skeletal issues: These conditions, which affect the structure of the spine, include scoliosis (curvature of the spine) and lordosis (a larger-than-normal inward arch in the lower back). While these underlying conditions often cannot be cured, medical professionals can usually work to alleviate the pain that they cause.
• Spina bifida: This birth defect occurs when a baby’s spinal cord develops incompletely or improperly. Spina bifida can cause severe back pain and even paralysis.
• Intervertebral disc degeneration: The discs between vertebrae (called intervertebral discs) help hold the vertebrae together and absorb impact in the spine. While they are usually rubbery and flexible, the intervertebral discs can become hard or worn down due to aging or injury. Lower back pain results when these discs can no longer effectively keep the vertebrae apart.
• Inflammatory diseases: Inflammatory diseases, including arthritis, rheumatoid arthritis, and spondylitis, all cause inflammation that can affect the lower back. This inflammation, which may or may not be painful, can occur in the muscles, ligaments, or even the vertebrae themselves.
• Spondylosis: This normal degeneration of the spine occurs due to age, wear and tear, and excessive or unusual use of the spine and back. Some athletes may develop early-onset spondylosis as a result of regular misuse or strain.
• Nerve problems: Both injury and normal wear and tear can cause the nerves in the spine to become compressed, injured, or inflamed, all of which can cause back pain.
• Herniated or ruptured discs: When a disc is compressed too much for too long, it can bulge out and put pressure on other tissues, which can cause lower back pain.
• Infections: Infection in the nerves, discs, and various joints in the back can cause inflammation and pain.
• Osteoporosis: This progressive condition causes the bones to degenerate in density and quality, increasing susceptibility to vertebral fractures. These fractures can lead to lower back pain that is sometimes severe.

In addition, there are several non-structural causes⁷ of lower back pain. These often indicate more serious conditions.

• Kidney stones: These hard deposits form in the kidneys cause pain that is usually sharp and severe, sometimes occurring only on one side of the lower back. Other symptoms include nausea, vomiting, difficulty passing urine, and blood in the urine.
• Fibromyalgia: Fibromyalgia, a syndrome that causes chronic, widespread pain, can sometimes affect the lower back.
• Endometriosis: This condition causes uterine tissue to build up outside the uterus, sometimes causing pain in the lower back.
• Tumors: Various types of tumors can put pressure on the spine or the tissues around it. They can also cause back pain by putting pressure on various parts of the lower back.
• Pregnancy: Many pregnant women experience lower back pain throughout their pregnancy or at different times during the course of it. In most cases, this pain goes away after giving birth.

Risk factors for lower back pain

Several factors⁸ can increase your risk of developing lower back pain, including:

• Age: People typically begin to experience lower back pain for the first time between the ages of 30 and 40 years old. Generally, however, the incidence of lower back pain increases with age, as the spine loses flexibility, the intervertebral discs become less elastic, and the likelihood of developing osteoporosis increases.
• Weight: Carrying excess weight puts pressure on the spine. People who are overweight or obese are more likely to experience lower back pain. Additionally, those who gain a significant amount of weight very quickly may find that the sudden increase in pressure causes lower back pain.
• Physical condition: Because weakened muscles can contribute to back pain, people who do not exercise regularly are more likely to experience lower back pain than those who do. Once back pain goes away, however, strengthening the muscles of the back and abdomen with exercise may keep the pain from returning.
• Genetics: Some genetically linked conditions, such as arthritis and fibromyalgia, can cause lower back pain.
• Diseases: Certain diseases, including arthritis and certain types of cancer, can cause lower back pain.
• Psychological conditions: Those who are affected by depression and anxiety appear to be more likely to have lower back pain than those without the disorders. Additionally, people who are stressed or who rate their psychological well-being as low may experience lower back pain more frequently.
• Smoking: Smoking reduces the flow of blood to the lower spine. As a result, the discs in the back may not receive sufficient nutrients, which can cause them to degenerate more quickly than normal. Additionally, smoking can slow the healing process, so lower back pain caused by strain or injury may last longer in smokers than in nonsmokers.
• Improper lifting technique: Using the back to lift (instead of the legs) can cause a strain or sprain that results in lower back pain.
• Occupational demands: Working a job that requires frequent heavy lifting or pushing, pulling, twisting, or vibrating motions can lead to lower back pain. Additionally, however, sitting in a chair for prolonged periods of time without proper back support or with poor posture can also cause lower back pain.

Lower back pain symptoms

While the symptoms⁹ of lower back pain generally encompass any forms of discomfort in the lower back, those with the condition often describe the following sensations:

• Muscle aches in the lower back
• Shooting or stabbing pain in the lower back
• Lower back pain that radiates down one or both legs
• Pain that lessens when the body is in a reclined position
• Pain that may worsen when walking, standing, bending, or lifting

If you experience lower back pain, talk to your healthcare provider. While you may not require medical treatment, you may be referred to a physical therapist or specialist that can teach you exercises to strengthen your muscles and help improve your signs and symptoms.

Complications from lower back pain

Especially when left untreated, lower back pain can result in a number of complications¹⁰. These may include:

• Muscle deconditioning: Constant pain can prevent regular movement or exercise. This can cause the muscles in the back to become weakened, lessening spine and joint support and potentially leading to further injury.
• Bone weakness: As is seen in the muscles, the bones may become weaker and more prone to fracture if back pain prevents movement for an extended period of time.
• Joint stiffness and weakness: Unused joints may frequently feel stiff and weak. This can lead to further injury unless the joints are rehabilitated correctly.
• Missed work: Lower back pain is one of the leading causes of missed work. This is particularly true when the job itself is contributing to the back pain. Severe lower back pain may require an individual to take time off of work for a period of time while they rehabilitate.
• Weight gain: When lower back pain makes physical activity difficult, weight gain often ensues. This can create a complicated feedback loop, as weight gain can cause even more back pain.
• Depression: As with many chronic pain conditions, constant or long-lasting lower back pain can have a significant impact on quality of life. This can lead to depression and other mental health disorders (which, as with weight gain, can further contribute to lower back pain).