Sitting is the New Smoking: How Prolonged Sitting is Slowly Killing Your Spine

Written By Cuan Wayne Coetzee .

Welcome back to MoveMed! Today, we tackle one of the most overlooked threats to your spinal health: prolonged sitting. In modern life, many of us spend far too long seated—whether at our desks, in front of screens, or commuting. And just like the public health wake-up call about smoking, we’re now recognising that prolonged sitting is devastating for our bodies, especially our spines.

Why Sitting Fatigues the Spine

When you sit for long periods, the core muscles that usually support your spine begin to fatigue. As these muscles tire, your posture collapses, and you begin to “sit” on your intervertebral discs. As I’ve written in previous blogs, discs function like water balloons—they can only handle so much pressure before they start to bulge. Sitting puts a strain on these discs, making them more vulnerable to injury.

Recent research has highlighted the connection between prolonged sitting and the development of disc issues. According to a study extended sitting is linked to increased disc pressure, especially in the lumbar spine, which can lead to pain and dysfunction .

Shortened Hip Flexors and the Domino Effect

But that’s not all. Sitting also shortens the hip flexors, particularly the iliopsoas muscle, which connects your lower spine to your hip. When this muscle is tight, it pulls on your spine, causing poor alignment and reduced mobility. This, in turn, leads to tight hamstrings and a downward pull on your spine when standing. It’s a vicious cycle that creates chronic tension and stress in your lower back.

Inactive Glutes: The Sleeping Giant of Movement Patterns

Let’s not forget the glutes—those powerful muscles that should be doing a lot of the work when you move. When you sit for hours on end, your glutes effectively go to sleep, or "deactivate." This can have a ripple effect on other key movement patterns, such as squatting, walking, or lifting. Without active glutes, your body compensates in inefficient and often harmful ways, putting even more stress on your spine.

Inactive glutes are strongly associated with poor posture and lower back pain. A study found that reduced glute activation during movement patterns increases the risk of lower back injuries, making it essential to incorporate regular glute activation exercises into daily routines .

The Fix: Regular Breaks and Posture Resets

Now, here’s the good news—sitting isn’t inherently bad. In fact, it’s not about never sitting, but rather about using sitting as a break from more optimal movement patterns. The key is to take regular breaks and perform posture resets throughout the day. Stand up, stretch, and move around every 30-60 minutes. This simple habit can make all the difference for your spine, hips, and overall health.

If you must sit, ensure you’re sitting with proper posture—upright, with your feet flat on the floor and your core engaged. Another great option is a standing desk, which allows you to alternate between sitting and standing, giving your body the movement variability it craves.

The Sitting-Year: A Practical Tool for Patient Education

When doctors discuss the relationship between smoking and cancer, they use a measurement called pack-years to quantify a person’s lifetime tobacco exposure. A pack-year is calculated by multiplying the number of packs smoked per day by the number of years smoked. This helps clinicians assess the risk of developing tobacco-related diseases.

I propose a similar concept for sitting: the sitting-year. A sitting-year is a unit for measuring the amount of time a person has spent sitting incorrectly over their life. It’s calculated by multiplying the number of days spent sitting (for more than six hours per day) by the number of years in their job. So, if someone sits for six hours a day for one year, that’s one sitting-year. Multiply that by five years, and you have five sitting-years.

Why is this important? Just like pack-years help doctors assess lung cancer risk, sitting-years can help us understand the long-term impact of prolonged, incorrect sitting on your spine and overall health. While it’s a rough estimate and not a direct indicator of back problems, the correlation I’ve seen in private practice is undeniable. Many patients with chronic disc issues or back pain have racked up decades of sitting-years, which may have contributed to their condition.

The Takeaway: Break the Cycle

In summary, prolonged sitting is a silent killer for your spine, but it doesn’t have to be. The damage caused by sitting on fatigued core muscles, shortened hip flexors, and inactive glutes can be reversed with regular movement, posture corrections, and body awareness.

Take hourly breaks from sitting, sit properly when you do, and, if possible, consider standing desk options to minimise the risks. Remember, sitting is just another form of movement, and like all movement, it’s best done in moderation.

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References:

  1. Ahn, S.-E.; Lee, M.-Y.; Lee, B.-H. Effects of Gluteal Muscle Strengthening Exercise-Based Core Stabilization Training on Pain and Quality of Life in Patients with Chronic Low Back Pain. Medicina 2024, 60, 849. https://doi.org/10.3390/medicina60060849

  2. Jeong UC, Sim JH, Kim CY, Hwang-Bo G, Nam CW. The effects of gluteus muscle strengthening exercise and lumbar stabilization exercise on lumbar muscle strength and balance in chronic low back pain patients. J Phys Ther Sci. 2015 Dec;27(12):3813-6. doi: 10.1589/jpts.27.3813. Epub 2015 Dec 28. PMID: 26834359; PMCID: PMC4713798. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4713798/

  3. Avrahami D, Potvin JR. The clinical and biomechanical effects of fascial-muscular lengthening therapy on tight hip flexor patients with and without low back pain. J Can Chiropr Assoc. 2014 Dec;58(4):444-55. PMID: 25550670; PMCID: PMC4262809. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4262809/

  4. Konrad A, Močnik R, Titze S, Nakamura M, Tilp M. The Influence of Stretching the Hip Flexor Muscles on Performance Parameters. A Systematic Review with Meta-Analysis. Int J Environ Res Public Health. 2021 Feb 17;18(4):1936. doi: 10.3390/ijerph18041936. PMID: 33671271; PMCID: PMC7922112. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922112/

  5. Wu, B., Gao, X., Qin, B. et al. Effect of microgravity on mechanical loadings in lumbar spine at various postures: a numerical study. npj Microgravity 9, 16 (2023). https://doi.org/10.1038/s41526-023-00253-8

  6. Zhou, M., Theologis, A. A., & O’Connell, G. D. (2024). Understanding the etiopathogenesis of lumbar intervertebral disc herniation: From clinical evidence to basic scientific research. JOR Spine, 7(1), e1289. https://doi.org/10.1002/jsp2.1289

  7. Iatridis JC, MacLean JJ, Roughley PJ, Alini M. Effects of mechanical loading on intervertebral disc metabolism in vivo. J Bone Joint Surg Am. 2006 Apr;88 Suppl 2(0 2):41-6. doi: 10.2106/JBJS.E.01407. PMID: 16595442; PMCID: PMC3697474. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3697474/

  8. Fu F, Bao R, Yao S, Zhou C, Luo H, Zhang Z, Zhang H, Li Y, Yan S, Yu H, Du W, Yang Y, Jin H, Tong P, Sun ZT, Yue M, Chen D, Wu C, Ruan H. Aberrant spinal mechanical loading stress triggers intervertebral disc degeneration by inducing pyroptosis and nerve ingrowth. Sci Rep. 2021 Jan 12;11(1):772. doi: 10.1038/s41598-020-80756-6. PMID: 33437038; PMCID: PMC7804398. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804398/   

Cuan Wayne Coetzee .
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