Chronic low back pain (CLBP) is the leading cause of disability in the US. Over 250 million works days are lost each year to CLBP. The cost in lost productivity and wages is over $100 billion dollars a year. Doctors know exercise helps CLBP. Science just can’t decide on why.
Science has overwhelmingly proven that exercise provides relief from chronic low back pain. Apparently, however, after decades of research, science still can’t agree on how it happens. That’s been reinforced by a new systematic review from the University of New South Wales (UNSW) Sydney.
Researchers from UNSW worked with colleagues from Neuroscience Research Australia (NeuRA) to produce the study, which was published in Musculoskeletal Science and Practice. Their goal was to get a better idea of why those researching back pain believe exercise can provide relief for CLBP.
They finished their work with no better idea of why exercise helps relieve back pain than when they started. The lack of clear agreement among scientists on this subject surprised them, as the study’s senior author, Dr. Matt Jones shared.
“Therefore, despite decades of research in the area and more than 100 studies we analyzed in our review, we still do not have a good idea of why exercise might be effective for CLBP,” Dr Jones said.
“Both in Australia and globally, low back pain (LBP) is the leading cause of disability and has been for the past few decades. LBP is associated with a significant burden both for the individual and society — i.e., through healthcare costs.
“A lot of treatments have stemmed from studies for people with CLBP (for example, medications, manual therapy, cognitive behavioral therapy), but the one with the most consistent evidence of benefit is exercise.”
Chronic low back pain is generally described as pain on the back of the body in the region between the base of the rib cage and the bottom of the backside. It generally lasts three months or longer.
“It’s the kind of pain that extends beyond the expected healing time of the body tissue. We also know that for many people, it is part of their daily lives and can significantly impact their quality of life,” he said.
“Today’s evidence suggests CLBP likely comes from the brain and nervous system being a bit over-protective and generating a pain response — despite no obvious physical damage to the body.”
Getting fitter, feeling stronger and better.
The researcher’s review was extensive. They analyzed 110 research studies, which included several thousand chronic low back pain sufferers. The papers came from the Physiotherapy Evidence Database (PEDro) and each dealt with why back pain researchers believe exercise can help relieve CLBP.
The studies were conducted in countries all over the world and cover a period of nearly three decades. The United States, China, Europe, Brazil and Australia were all represented.
Despite finding a consistent lack of agreement about why exercise relieves low back pain in all that data, Dr. Jones noted that they did find some common ground.
“Researchers proposed common reasons as to why exercise was beneficial, including improvements in fitness — for example, core stability, aerobic fitness — and improvements in mood and confidence,” he said.
“But the effects of these proposed reasons on outcomes for people with CLBP were seldom examined in the papers.
“In one-third of studies, researchers did not even propose a reason for why they thought exercise might be effective.”
Dr Jones said the jury was still out on why exercise worked for people with CLBP because chronic pain was a complex condition.
“Chronic pain is tricky and there are a lot of factors that can contribute to it — so, it’s not simply biological aspects of tissue damage, but there are psycho-social elements at play, as well things like a person’s mood or confidence in their own abilities to do something,” he said.
“There have been trends in research over time, where everyone focuses on a ‘flavor of the month’ — like motor control or McKenzie therapy, for example — but because the effects of exercise are broad and it impacts on many different systems in the human body, it’s difficult for researchers to pinpoint exactly why they think it might be benefiting people with pain.”
So now what?
Professor James McAuley of UNSW stated that the review of evidence was part of a larger effort aimed at understanding the mechanisms of how exercise relieves CLBP. McAuley leads a team of 30 researchers who are focused on the improvement of chronic pain management.
“Future primary studies could involve randomized controlled trials designed to investigate the mechanisms of benefit identified in our review. For example, mechanisms such as improving strength, improving self-efficacy — someone’s belief in their ability to perform tasks despite pain — and others,” Prof. McAuley said.
“The answer could also be achieved by using a technique called ‘mediation analysis’ which seeks to identify mechanisms of benefit in trials that have already been conducted. If we can identify why exercise works, then we can design treatments to maximize its benefits.
“Pain is very complex — so, in all likelihood, it will be a combination of many factors that lead to the consistent improvements in pain and function after exercise for people with CLBP.”
Physical activity and chronic pain
This review didn’t address evidence pointing to which specific exercises had the biggest effect on CLBP. Dr. Jones suggested that people who are suffering with chronic low back pain find exercises they can do consistently and feel safe and reassured about.
“Many scientists have investigated this question before and the short answer is, there are no specific exercises recommended to alleviate CLBP,” he said.
“But there are literally hundreds of studies on exercise for people with chronic pain, not only CLBP, and researchers consistently find exercise is one of the most effective treatments — it might not cause huge reductions in pain and disability, but it does help.
“So, remaining physically active and being reassured it is safe to do so — it is rare that chronic pain is caused by ‘issues with the tissues’ — is probably the simplest, best advice for someone with chronic pain.”
Dr Jones believes that people with CLBP have plenty of options when it comes to choosing safe, effective exercises and activities. “This might be through structured exercise (for example, going for a jog, going to the gym), but it could be other activities or hobbies people enjoy doing as well, such as gardening, surfing, walking the dog or mowing the lawn,” he said.
“It is important the activities are progressed slowly and if they do aggravate someone’s pain slightly that is okay, because staying sedentary is no longer a recommended option.
“But if you are unsure about what activities or exercise would work for you, ask your GP who could refer you to a physiotherapist or find an accredited exercise physiologist.”
Scientists around the world may have their own thoughts on why exercise interventions work for people with chronic low back pain. But they can all probably agree that they can’t agree on those reasons.
For more than two decades, I have used progressive exercise interventions to help my clients (and myself) deal with chronic low back pain. CLBP can take over your life, leading to diminished enjoyment of life, depression and anxiety. But exercise will help. That much I’m sure of. I just wish we could figure out why.
Keep the faith and keep after it!
Journal Reference – Annika Wun, Paul Kollias, Harry Jeong, Rodrigo RN. Rizzo, Aidan G. Cashin, Matthew K. Bagg, James H. McAuley, Matthew D. Jones. Why is exercise prescribed for people with chronic low back pain? A review of the mechanisms of benefit proposed by clinical trialists. Musculoskeletal Science and Practice, 2021; 51: 102307 DOI: 10.1016/j.msksp.2020.102307