21 July 2025

Low back pain is the leading cause of disability worldwide. On any given day, almost 14 per cent of Australians suffer from back pain – that’s one person in every seven – and hence, it is the most common musculoskeletal condition seen by general practitioners. Acute low back pain is pain in the region of the lumbar spine (see diagram below) that comes on suddenly, for example as the result of a sports injury, or picking up a heavy load with improper lifting technique, or digging a garden bed. Chronic low back pain is defined as lumbar pain that persists for longer than three months.

One of the most common misconceptions about chronic low back pain is that it’s most likely to afflict working-age adults whose jobs involve heavy lifting, prolonged standing, or having to hold awkward positions for extended periods of time (think tilers, plumbers, hairdressers and dentists). Acute low back pain is certainly an occupational hazard for many, but mechanical factors are not the driving cause of chronic low back pain:

“Eight systematic reviews with the Bradford-Hill causation criteria concluded that it was unlikely that occupational sitting,³⁴ awkward postures,³⁵ standing and walking,³⁶ manual handling or assisting patients,³⁷ pushing or pulling,³⁸ bending and twisting,³⁹ lifting,⁴⁰ or carrying⁴¹ were independently causative of low back pain in the populations of workers studied.”

Non-specific low back pain

In fact, the prevalence of chronic low back pain increases with age:

And that age distribution gives clues about the true underlying causes of chronic low back pain. Chief among those underlying causes are a) atherosclerotic plaque that occludes the lumbar arteries; and b) inadequate physical activity. Atherosclerosis increases with age, steadily over the life course in males, and accelerating rapidly after menopause in females. (Take another look at figure 2 above, and note the large jump in prevalence of low back pain as women age up from the 45-54 year old cohort to the 55-64 year old cohort; this increase corresponds with the increased risk for atherosclerosis in women over 55.) Most people also exercise less and spend more time sitting as they get older.

I was prompted to write about low back pain by a recent study titled ‘Volume and Intensity of Walking and Risk of Chronic Low Back Pain‘, which I’ll return to shortly, but first let’s briefly review the role that atherosclerosis plays in chronic low back pain.

Atherosclerosis and back pain: What’s the connection?

The spine is a highly vascular structure, as you can see in this schematic diagram:

That complex network of blood vessels delivers vital nutrients and oxygen directly to the muscles, bones, ligaments and nerves which comprise the spinal column, and flushes away their waste products. The intervertebral discs, however, are avascular – that is, they don’t have blood vessels running through them. Instead, they are indirectly supplied with nutrients and cleansed of wastes, relying on diffusion from and to blood vessels in the vertebral bodies above and below them.

As a direct result of this somewhat precarious nutrient supply, the intervertebral discs are highly susceptible to the diminished blood flow that occurs when atherosclerotic plaques begin to occlude (block off) the openings to the lumbar and sacral arteries. The figure on the right, which is a section of the abdominal aorta, shows what that occlusion looks like:

… and the aortograph below shows the effect on blood supply of this occlusion:

People with atherosclerotic plaque in the feeding arteries of the lumbar spine are more likely to have disc degeneration and low back pain. So, what causes these atherosclerotic plaques? The major risk factor for disc degeneration and chronic low back pain, in both epidemiological studies and cross-sectional analysis of patients, is elevated serum LDL cholesterol.

Yes, aside from jacking up your risk of coronary heart disease, depression and Alzheimer’s disease, and ruining your sex life (whether you’re male or female), having high LDL cholesterol also increases your risk of back pain and neurogenic symptoms such as tingling, pins and needles, and pain radiating down the legs.

The link between chronic low back pain, elevated LDL cholesterol and atherosclerosis is so strong, that some authors have suggested that chronic lumbar pain should be treated as a ‘canary in the coal mine’ for atherosclerotic heart disease, along similar lines to erectile dysfunction in men. Both the penile artery and the arteries that indirectly supply the intervertebral discs with blood, are smaller in diameter than the coronary arteries, so if a person is developing atherosclerotic plaque throughout their vascular system, the reduced blood flow will manifest in erectile dysfunction and back pain long before the coronary arteries clog up sufficiently to cause angina or a heart attack.

If you suffer from chronic low back pain, I highly recommend getting a blood test for LDL cholesterol (or, even better, for apolipoprotein B). If your levels of one or both are elevated, I strongly advocate the Portfolio Diet developed by Dr David Jenkins, which is the most effective dietary approach for reducing LDL cholesterol.

Let’s turn now to the second major predictor of chronic low back pain: physical activity level.

Low back pain and physical activity

For people who already have chronic low back pain, resuming exercising is key to recovery (especially since painkillers and surgery are ineffective or harmful in most cases). And in cross-sectional studies, people who are physically active have a lower risk of chronic low back pain. But such studies are subject to the reverse causation fallacy – that is, it is possible that not having chronic low back pain caused higher physical activity levels, rather than the higher physical activity levels preventing low back pain.

To establish the direction of causation, you need a prospective cohort study that recruits participants who do not have chronic low back pain, or any other disabling condition, at baseline, and then follows them up over time to see whether those with a higher physical activity level have less back pain. And since walking is the most easily-accessible form of physical activity for people of all ages, especially older people who have a higher risk of chronic low back pain, it would be ideal to study walking volume in a cohort of people, including substantial numbers of older people.

Et voilà. In a Norwegian population-based cohort study including 11 194 participants with an average age of 55 at baseline, walking volume (the number of minutes of walking time per day) was inversely related to the risk of developing chronic low back pain. Almost 15 per cent of participants reported chronic low back pain at the follow-up point, which was roughly 4.2 years after recruitment, but those who walked for more than 100 minutes per day had a 23 per cent lower risk compared to those who walked less than 78 minutes per day. Most conditions that researchers study are quite rare, so a relative risk reduction of 23 per cent is usually bugger all of nothing. But for a malady as common as chronic low back pain, lowering the risk by nearly a quarter is clinically meaningful – meaning that it actually matters from the point of view of the patient (or the person who wishes to avoid becoming a patient!).

Walking intensity (essentially, speed of walking) also played a role; participants with the highest walking intensity had an 18 per cent lower risk of developing chronic low back pain than those who walked the slowest. But walking for longer at a slower speed ended up being about as beneficial as walking faster but for a shorter duration.

The authors of the study were well aware of the problem of reverse causation, so they excluded anyone who had chronic low back pain or any other chronic pain condition from participation, as well as people in poor health or with a history of conditions that might reduce walking capacity. Given the influence of socioeconomic and demographic factors on chronic pain, all associations were statistically adjusted for age, sex, education level, household income, employment status, smoking status, and depression.

Walking volume and intensity were measured over the course of seven days, using two tri-axial accelerometers, one placed centrally on the right thigh and other on the lower back. The researchers were able to differentiate between walking and other forms of physical activity, such as running and cycling, using a machine learning classifier.

Both males and females benefitted equally from walking for longer than 100 minutes per day. And, in encouraging news for the more mature among us, higher walking volume appeared to be even more protective against chronic low back pain in people over 65 than in younger folk.

Now, you might be thinking, “I don’t have time to walk for over an hour and forty minutes per day!” But remember that the accelerometers measured walking time across the whole day, not just time spent in intentional exercise. Increased daily walking time translates pretty well to decreased time spent sitting. Humans are built for walking, not for sitting on our butts all day.

Given the enormous financial and psychosocial costs of chronic low back pain, promoting walking as a prevention tool is a no-brainer, as the authors of the study emphasise:

“If confirmed by future research, these results could inform public health strategies aimed at preventing chronic LBP, as well as complementing current guidelines that solely report on physical activity as a secondary prevention tool.^6,34–39 The potential role of walking could be further promoted owing to its ease of implementation, accessibility, and numerous health benefits beyond reducing the risk of chronic LBP.^40,41“

Volume and Intensity of Walking and Risk of Chronic Low Back Pain

Walking is not sexy, it’s not high tech, and it doesn’t make anyone any money (except for shoe manufacturers, I guess), but, when combined with a healthy cholesterol-lowering eating pattern such as the Portfolio Diet, walking for longer than 100 minutes per day will do more to protect you from developing chronic low back pain than any high-priced gadget you’ve seen in an infomercial.

How many minutes did you walk today?

Are you confused by the scientific claims and counter-claims that you encounter through popular and social media? Would you like to learn how to read scientific research, assess its biases, and understand how it fits within the body of scientific literature? My EmpowerEd membership program is custom-made for you. Activate your free 1-month trial today!