Written by the Nuvirox Research Team
Key points
- Chronic pain drains energy by three separate routes: fragmented sleep, continuous cognitive load, and a sensitised nervous system.
- Insomnia is highly prevalent in chronic pain and is closely tied to central sensitisation — and it responds poorly to drug treatment.
- CBT for insomnia has trial evidence for improving both sleep and pain interference in people living with chronic pain.
Short answer: yes, and the exhaustion is usually out of proportion to the pain itself. That mismatch is not a sign of weakness or exaggeration; it reflects the fact that pain taxes the body through at least three separate channels simultaneously. It fragments sleep. It occupies attention continuously. And in longer-standing pain it involves a nervous system running at higher gain, which is metabolically and cognitively expensive to maintain. The fatigue is a predictable consequence of the physiology, not an add-on complaint.
Route one: pain fragments sleep, even when you think you slept
People with chronic pain frequently report sleeping through the night and waking unrefreshed. Sleep studies help explain this. Pain is associated with frequent brief arousals that do not reach conscious awareness but disrupt sleep architecture, reducing time in the deep, slow-wave stages that appear most important for feeling restored.
The result is a night of nominally adequate duration and materially degraded quality. This is the same phenomenon we describe in waking up tired despite sleeping enough, arriving by a different route.
The relationship also runs backwards, which is the trap. Experimental sleep restriction lowers pain thresholds in healthy volunteers. So a poor night worsens the next day's pain, which worsens the next night's sleep. The loop closes.
Route two: pain consumes attention continuously
Pain is designed to capture attention. That is its evolutionary function — it is an interrupt signal that overrides whatever you were doing. When the signal is acute and brief, this works well. When it persists for months, the interrupt never stops firing.
The cognitive cost is measurable. People in chronic pain perform less well on attention and working memory tasks, and describe a mental fog that is often more disabling than the pain itself. Part of that is the pain competing for attentional resources; part is the additional executive effort of continuously suppressing it in order to function. Both are expensive, and both show up as mental fatigue by mid-afternoon.
Route three: central sensitisation
In longer-standing pain, the nervous system itself changes. Central sensitisation describes a state in which spinal and brain pain-processing pathways become more responsive, so that a given input produces a larger output. Clinically it looks like pain that is disproportionate to any identifiable tissue damage, spreads beyond the original site, and comes with hypersensitivity to touch, light, sound, and temperature.
A systematic review of 34 studies examining central sensitisation in chronic low back pain concluded that the concept is assessed through twenty different quantitative methods with forty different definition references — which is a polite way of saying the construct is real but imprecisely measured. The authors proposed the term "human assumed central sensitisation" to acknowledge that it cannot be directly observed in people. Notably, fatigue, non-restorative sleep, and difficulty concentrating are listed among its recognised associated symptoms.
What human studies actually show
Insomnia in chronic pain is highly prevalent, mechanistically linked, and drug resistant. A review in Physical Therapy concluded that insomnia among people with chronic pain is closely related to central sensitisation, characterised by low-grade neuroinflammation, commonly associated with stress or anxiety, and does not respond effectively to pharmacological treatment. That last clause matters: the obvious intervention is the one that works least well.
Cognitive behavioural therapy for insomnia does work. The same review found CBT-I efficacious for sleep initiation, sleep maintenance, perceived sleep quality, and — importantly — pain interference with daily functioning in people with chronic pain. It improves both sides of the loop.
Sleep deprivation drives neuroinflammation, which drives sensitisation. The proposed mechanism involves sleep deprivation and chronic stress acting as glial activators, increasing circulating pro-inflammatory cytokines including TNF-alpha and IL-6, and contributing to the onset or persistence of hyperalgesia. This connects chronic pain fatigue to the broader inflammatory picture.
The honest counterweight: pain education helps less than its enthusiasts claim. A systematic review of 15 randomized trials of pain neuroscience education in chronic musculoskeletal pain with central sensitisation found the outcome measures too heterogeneous to meta-analyse, with results varying substantially by diagnostic subgroup. It appears to help, particularly combined with other approaches, but it is not the reliable intervention it is sometimes presented as.
Study snapshot
| Review | Nijs et al., Physical Therapy, 2018 |
| Focus | Insomnia in people with chronic pain |
| Key findings | Insomnia highly prevalent; tied to central sensitisation and low-grade neuroinflammation; poor response to drug treatment |
| What worked | CBT for insomnia improved sleep initiation, maintenance, quality, and pain interference with daily activities |
| Limitation | Optimal timing and sequencing of sleep treatment in chronic pain remains undefined |
What this framing won't do
It will not tell you your pain is psychological. Central sensitisation is a change in nervous system function, not a change in belief. This distinction gets muddled constantly and does real harm. The pain is generated by a physiological process; it is simply not a process located where the pain is felt.
It will not replace investigation of new or changing pain. See a doctor if pain is new, progressively worsening, follows an injury, or comes with fever, unexplained weight loss, night pain that wakes you, weakness, numbness, or bladder or bowel changes. Those features point toward causes needing prompt assessment. Established chronic pain that changes character deserves the same attention.
And it will not be solved by a supplement. There is no supplement with credible evidence for treating central sensitisation. If you have a diagnosis such as fibromyalgia, our review of NAD+ and fibromyalgia covers what the small trials in that specific condition have and have not shown.
What tends to actually help the fatigue
Treating the sleep directly is the highest-yield move, and CBT-I specifically has the evidence behind it. Paced activity — working to a consistent baseline rather than doing a great deal on good days and collapsing afterwards — reduces the boom-and-bust pattern that amplifies fatigue. Graded movement, built slowly, improves both pain and energy in most chronic pain conditions despite feeling counterintuitive. And reviewing medication matters more than people expect: several drugs commonly prescribed for chronic pain, including gabapentin and opioids, cause sedation and fatigue in their own right, which is worth separating out from the pain itself.
Frequently asked questions
Why am I more tired than the pain seems to justify?
Because the fatigue is not driven by pain intensity alone. Sleep fragmentation, continuous attentional load, and a sensitised nervous system each contribute independently, so someone with moderate pain and badly fragmented sleep can be more exhausted than someone with severe pain who sleeps well.
Will treating my pain fix the fatigue?
Often partly, but not always fully. If sleep has been disrupted for a long time or a boom-and-bust activity pattern is established, those persist after pain improves and need addressing separately.
Is chronic pain fatigue the same as chronic fatigue syndrome?
No, though they overlap and can coexist. ME/CFS has its own diagnostic criteria centred on post-exertional malaise. Fatigue secondary to chronic pain is a consequence of the pain condition rather than a separate diagnosis.
Do painkillers help the tiredness?
Sometimes indirectly, by improving sleep. But many analgesics cause sedation themselves, and opioids in particular disrupt sleep architecture even while reducing pain, which can leave someone in less pain and no less tired.
Does exercise make it worse?
Done too aggressively, yes. Built gradually from a sustainable baseline, graded activity improves pain, sleep, and energy across most chronic pain conditions. The failure mode is pace, not the exercise.
From Nuvirox
Why we formulated NAD+ Restore
NAD+ Restore supports cellular energy metabolism with nicotinamide riboside at a trial-relevant dose. We want to be straightforward: it is not a pain treatment, and no supplement has credible evidence for central sensitisation.
- 500 mg Nicotinamide Riboside Chloride (NR) — one of the two most-researched NAD+ precursors, within the dose range used in published human trials.
- 150 mg trans-resveratrol (Japanese Knotweed) and 50 mg quercetin (Sophora japonica) — polyphenols studied alongside NAD+ pathways for cellular health support.
- 10 mg galactomannans from fenugreek, to support absorption.
- 60-day money-back guarantee — long enough to actually evaluate it the way the research says you should.
Chronic pain with significant fatigue deserves a proper clinical assessment, and sleep is usually the highest-yield place to start. Ask your doctor specifically about CBT for insomnia and about reviewing whether any of your current medications are contributing to the tiredness.
The bottom line
Chronic pain is exhausting for reasons that are physiological and well described. It fragments sleep in ways that do not show up as waking, it occupies attention continuously, and over time it recruits a nervous system that runs hotter than it should. The most productive place to intervene is usually sleep, because it sits at the centre of the loop and because CBT for insomnia has trial evidence for improving both the sleep and the pain interference. That is a less satisfying answer than a supplement, and a considerably better supported one.
References
- Nijs J, Mairesse O, Neu D, et al. Sleep disturbances in chronic pain: neurobiology, assessment, and treatment in physical therapist practice. Physical Therapy. 2018;98(5):325–335. DOI: 10.1093/ptj/pzy020
- Schuttert I, Timmerman H, Petersen KK, et al. The definition, assessment, and prevalence of (human assumed) central sensitisation in patients with chronic low back pain: a systematic review. Journal of Clinical Medicine. 2021;10(24):5931. DOI: 10.3390/jcm10245931
- Bonatesta L, et al. Effectiveness of pain neuroscience education in patients with chronic musculoskeletal pain and central sensitization: a systematic review. Journal of Pain Research. 2022. PMCID: PMC10001851
- Custodero C, Mankowski RT, Lee SA, et al. Evidence-based nutritional and pharmacological interventions targeting chronic low-grade inflammation in middle-age and older adults: a systematic review and meta-analysis. Ageing Research Reviews. 2018;46:42–59. PMID: 29803716. DOI: 10.1016/j.arr.2018.05.004
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for professional medical advice.