Modern life has progressively separated us from the natural light-dark cycle that has shaped human biology for millions of years.
We now spend up to 90% of time indoors (Bunn et al., 2023), are exposed to artificial light late into the evening, and increasingly eat and sleep at times that are misaligned with our internal biological clocks. Emerging research suggests that this circadian disruption may matter for more than sleep and metabolic health – it may also influence how well people recover from low back pain and sciatica.
Circadian rhythm is the bodies internal physiological processes oscillating in synchrony to daily environmental patterns. The most consistent daily pattern since the evolution of life from single-celled organisms millions of years ago has been natural sunlight but others include feeding, activity and ambient temperature (Wright et al., 2013; Roenneberg et al., 2016).
Circadian health is a whole-body phenomenon, and its ill-health has body-wide consequences.
Every cell is under the control of clock genes, and their stimulus comes from the signals sent from specialised nerve cells in the eye in response to light particles (Roenneberg et al., 2016). Complex changes take place in an area in the brain called the suprachiasmatic nucleus, known as the master clock, where certain genes are turned on, and others off during the presence of light and darkness respectively.
Through hormonal and chemical signalling, peripheral clocks in the in the liver, muscles and other organs also undergo daily diurnal changes (Roenneberg et al., 2016) in response to the master clock. Consequently, these diurnal changes in physiological processes in the body regulate everything from sleep, our ability to digest food, deal with stress, right down to your immune function and capacity to fight off infection.
It is now well established that every system in the body has a natural circadian rhythm to it; the ones relevant to low back pain include the endocrine, immune and neurological system that all show strong circadian regulation (Roenneberg et al., 2022).
Persistence of low back pain is a whole-body problem, not just in the spine
The three systems mentioned above are responsible for the persistence of low back pain and its recovery trajectory.
In people who develop first-time acute low back pain episode, alterations in T-cell and B-cell expression and higher baseline innate immune sensitivity predict the transition from acute to chronic low back pain, independent of age or sex (Brown et al., 2025). This is supported by multiple review papers showcasing the role of neuro-immune interactions and its ability to regulate pain intensity and persistence independent of structural changes in joints (Schipholt et al., 2026; Brezic et al., 2026).
Your hormonal health also appears to play a key role in pain sensitivity and recovery.
Dysfunction of the hypopituitary adrenal axis (HPA) in people with persistent back pain and its negative association to pain sensitivity and recovery has been well evidenced (Azeez et al., 2025; Sanabria-Mazo et al., 2022). This is thought to occur secondary to impaired regulation of pain pathways because of glucocorticoid receptor desensitization, flattened diurnal cortisol rhythms, chronic hypercortisolaemia, and sustained catecholaminergic tone (Azeez et al., 2025).
Impaired function of other hormones including leptin, adiponectin, insulin, testosterone and oestrogen has been linked to increased pain sensitivity and impaired recovery in pre-clinical studies and human trials (Ozcan et al., 2024).
The peripheral and central divisions of the nervous system and related pathways involved in pain sensing and inhibition show changes culminating in increased sensitisation and impaired ability to inhibit pain via descending pain inhibitory pathways, further contributing to pain severity and persistence (Li et al. 2021).
If these systems have the capacity to regulate recovery from low back pain, and each show a strong circadian rhythm, then there may well be a link between our circadian health and low back pain recovery.
People with poor circadian health struggle to recover from low back pain.
This is exactly what is emerging in the scientific research.
In people who developed symptomatic low back pain and radicular leg pain, those who ate their largest meal in the evening had significantly worse symptoms and did not recover in 6-months when compared to those who ate at a circadian-appropriate time (Lie et al., 2026).
The lumbar disc itself has shown strong circadian regulation (Dudek et al., 2017) and a recent retrospective study of elderly people with low back and leg pain found a strong, positive association between poor circadian health and more advanced disc degermation see on magnetic resonance imaging (MRI) of the lumbar spine (Li et al., 2026). In the same study, the authors also noted a strong, positive correlation between concentrations inflammatory molecules in the blood and worse circadian health.
Existing review papers on preclinical human trials and animal studies have clearly shown impaired effectiveness of pain pathways in the context of poor circadian regulation (Warfield et al., 2021). This will no doubt influence neuro-immune-endocrine pathways involved in pain regulation and be contributing factor the circadian-related pain persistence and severity.
Taken together, the systems involved in the sensing and regulation of pain appear to be under circadian control highlighting the importance of bringing an awareness and assessment of circadian health into the physiotherapist-patient conversation when discussing low back pain.
Circadian health is not set in stone and can be improved with habits that realign our bodies to these diurnal patterns.
Realigning your circadian rhythm is achieved through prioritising early morning light and over the day, eating the bulk of your food in breakfast and lunch, and aiming to reduce your exposure to artificial light at night.
Getting early morning sunlight should be priority number one. For every 30-minutes of sunlight before 10am in the morning, we shift our circadian rhythm 23-minutes towards the normal, earlier advancement (de Menezes-Júnior et al., 2025).
Remember, light is our primary zeitgeber and thus it should be prioritised at every moment throughout the day.
The second is establishing a circadian-aligned eating habit.
This involves eating your largest meal at breakfast and lunch and your smallest meal in the evening. Your liver, muscles and other peripheral organs are under the control of feeding behavioural patterns. Eat earlier in the day when these organs are primed to digest and extract the nutritional value from the food we consume.
The final aspect of improving your circadian health is to minimise artificial light at night. This has been consistently shown to disrupt circadian rhythms and lead to a late evening chronotype (Wright et al., 2013), one associated with the neuro-immune-endocrine problems discussed above.
Low back pain with or without spinally referred leg pain is not a structural issue. It is a body-wide problem involving the neurological, immunological and endocrinological systems. Understanding that these systems are governed by circadian-clock genes and deviations from normal circadian patterns appears to underlie worse outcomes in low back and persistence of symptoms beyond the normal recovery trajectory, is quintessential.
People suffering with low back pain and leg pain should seek the care of physiotherapists — such as Tide Physiotherapy — who practise with an understanding of this system-wide approach to pain, whilst seeking to establish how their relationship with earths’ natural cycles might be hindering their recovery from back pain.
References
Brezic, N., Gligorevic, S., Sič, A., Tseriotis, V. S., & Knezevic, N. N. (2026). Sexually Dimorphic Neuroimmune Pathways in Chronic Pain: A Comprehensive Systematic Review of Cellular and Molecular Mechanisms. Biomolecules, 16(2), 258.
Schipholt, I. J. L., Coppieters, M. W., Scholten-Peeters, G. G., Hutchinson, M. R., & Klyne, D. M. (2026). Neuroimmune interactions in musculoskeletal conditions. An introduction for clinicians. Musculoskeletal Science and Practice, 81, 103469.
Azeez, O. M., Olaniyi, H., Obong, E., Dunkwu, C. C., Oyovwi, J. O., Oyovwi, M. I., … & Okafor, C. P. (2026). Epigenetic and Endocrine Adaptations Linking Chronic Pain, Metabolic Dysregulation, and Cardiovascular Remodeling: A Narrative Review. Cureus, 18(1).
Sanabria-Mazo, J. P., Colomer-Carbonell, A., Carmona-Cervelló, M., Feliu-Soler, A., Borràs, X., Grasa, M., … & Luciano, J. V. (2022). Immune-inflammatory and hypothalamicpituitary-adrenal axis biomarkers are altered in patients with non-specific low back pain: a systematic review. Front Immunol. 2022; 2 (13): 945513.
Brown, M. C., Kosinski, A. S., Fillipo, R., Howell, G., Giang, M. H., Hurewitz, M., … & Goode, A. P. (2025). Patterns and trajectories of peripheral inflammatory cytokines, immune tolerance, and lymphocyte differentiation predict transition from acute to chronic low back pain in a sex and age specific manner. Pain, 167(2), 477.
Roenneberg, T., & Merrow, M. (2016). The circadian clock and human health. Current biology, 26(10), R432-R443.
Bunn, S and Duffield, G (2023) Indoor Air Quality. URL accessed 14/9/26: https://post.parliament.uk/research-briefings/post-pb-0054/
Liu, C., Tong, Y., Pan, M., Chen, X., Yang, X., He, F., … & Xing, L. (2026). Synergistic impact of chrono-nutritional and pro-inflammatory dietary patterns on chronic pain recovery: a prospective cohort study with population-based corroboration. Frontiers in Nutrition, 13, 1798285.
Dudek, M., Yang, N., Ruckshanthi, J. P., Williams, J., Borysiewicz, E., Wang, P., … & Meng, Q. J. (2017). The intervertebral disc contains intrinsic circadian clocks that are regulated by age and cytokines and linked to degeneration. Annals of the rheumatic diseases, 76(3), 576-584.
Li, R., Wang, Z., Zhang, T., & Ren, Y. (2026). Circadian Rhythm Disorders in Elderly Patients With Lumbar Disc Herniation and Their Association With Serum Inflammatory Factors: A Retrospective Study. International Journal of Clinical Practice, 2026(1), 8737409.
Warfield, A. E., Prather, J. F., & Todd, W. D. (2021). Systems and circuits linking chronic pain and circadian rhythms. Front Neurosci. 15: 705173.
Ozcan, M., & Ayar, A. (2024). Endocrine aspects of pain pathophysiology: focus on adipose tissue. Neuroendocrinology, 114(10), 894-906.
Li, W., Gong, Y., Liu, J., Guo, Y., Tang, H., Qin, S., … & Chen, B. (2021). Peripheral and central pathological mechanisms of chronic low back pain: a narrative review. Journal of pain research, 1483-1494.
de Menezes-Júnior, L. A. A., Sabião, T. D. S., Carraro, J. C. C., Machado-Coelho, G. L. L., & Meireles, A. L. (2025). The role of sunlight in sleep regulation: analysis of morning, evening and late exposure. BMC public health, 25(1), 3362.
Wright, K. P., McHill, A. W., Birks, B. R., Griffin, B. R., Rusterholz, T., & Chinoy, E. D. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current biology, 23(16), 1554-1558.
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