Chronic pain lasting beyond normal tissue healing time, requiring a biopsychosocial treatment approach.
Persistent pain syndrome — also referred to as chronic pain syndrome — describes pain that continues beyond the normal expected timeframe for tissue healing, typically lasting longer than three months (Treede et al., 2015). Unlike acute pain, which serves as a protective warning signal for injury or illness, persistent pain often persists even after the original tissue damage has resolved. The International Association for the Study of Pain (IASP) recognizes chronic pain as a condition in its own right, not merely a symptom of another disease.
Persistent pain affects an estimated 20% of the global adult population, making it one of the most common reasons people seek physiotherapy and medical care. It can manifest in virtually any body region — the low back, neck, shoulders, hips, knees — and frequently involves widespread body areas simultaneously. Conditions such as fibromyalgia, chronic low back pain, persistent post-surgical pain, and complex regional pain syndrome all fall under this broad umbrella.
What distinguishes persistent pain from other pain conditions is the fundamental shift in how the nervous system processes sensory information. Rather than reflecting ongoing tissue damage, persistent pain represents a state in which the nervous system itself has become sensitized and begins generating pain signals in the absence of proportional tissue threat. This understanding forms the foundation of the biopsychosocial model of pain, which recognizes that biological factors (nerve sensitivity, inflammation, genetics), psychological factors (thoughts, emotions, beliefs about pain), and social factors (work environment, relationships, cultural context) all interact to shape the pain experience (Engel, 1977; Gatchel et al., 2007).
The biopsychosocial model represents a critical departure from the outdated biomedical view that pain always equals tissue damage. Research consistently demonstrates that the severity of pain a person experiences often does not correlate with the degree of structural findings on imaging. Many people with significant disc herniations or joint degeneration on MRI report no pain at all, while others with minimal structural changes experience debilitating pain. This disconnect underscores the importance of addressing the whole person — not just the tissue — when treating persistent pain.
Understanding how pain becomes persistent requires a basic appreciation of how the nervous system processes threat signals. In normal circumstances, specialized nerve endings called nociceptors detect potentially harmful stimuli — excessive pressure, extreme temperature, chemical irritation — and send electrical signals along peripheral nerves to the spinal cord and brain. The brain then evaluates these signals in the context of all available information (past experiences, current emotions, environmental cues, beliefs) and decides whether to produce the experience of pain.
When pain persists beyond normal healing times, several neurological changes occur that fundamentally alter this processing system:
Peripheral sensitization occurs when nociceptors in the tissues become more responsive and develop a lower threshold for activation. Inflammatory chemicals released during the initial injury can linger and keep nerve endings in a heightened state of alert, firing more easily and more intensely than normal.
Central sensitization is perhaps the most important mechanism in persistent pain. The neurons within the spinal cord and brain become hyperexcitable, amplifying incoming signals and even generating pain signals without adequate peripheral input (Latremoliere & Woolf, 2009). This means that stimuli that would normally be perceived as light touch or mild pressure can be interpreted as painful — a phenomenon known as allodynia. Similarly, mildly painful stimuli may produce exaggerated pain responses, termed hyperalgesia.
The IASP introduced the term nociplastic pain to describe this third mechanism of pain (alongside nociceptive and neuropathic pain) — pain arising from altered nociception despite no clear evidence of actual or threatened tissue damage or disease of the somatosensory system (Kosek et al., 2016). Functional MRI studies reveal that individuals with chronic pain show increased connectivity between brain regions responsible for sensory processing, emotion regulation, and attention, including the default-mode network and insular cortex.
Neuroplastic changes in the brain itself include alterations in the size, structure, and function of brain regions involved in pain processing. The prefrontal cortex, which plays a role in pain modulation and executive function, often shows reduced grey matter volume in chronic pain patients. The good news is that these changes appear to be reversible with effective treatment, particularly exercise and psychological interventions.
Additional central nervous system changes include upregulation of excitatory neurotransmitters (such as glutamate and substance P), downregulation of inhibitory neurotransmitters (such as GABA and serotonin), changes in descending pain modulation pathways, and immune cell activation within the central nervous system. These changes help explain why people with persistent pain often experience associated symptoms beyond pain itself, including fatigue, sleep disturbance, cognitive difficulties (sometimes called "brain fog"), and mood changes.
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Research has identified a broad range of biopsychosocial factors that increase the likelihood of acute pain transitioning into a chronic condition. A landmark umbrella review and meta-analysis published in PLOS ONE identified 34 biopsychosocial factors associated with the development of chronic musculoskeletal pain (Caneiro et al., 2024). Understanding these risk factors is essential for early identification and prevention.
Physiotherapy occupies a central role in the management of persistent pain because it addresses the condition through multiple evidence-based mechanisms simultaneously. Unlike passive treatments that target a single dimension of the pain experience, physiotherapy integrates movement, education, and behavioural strategies to address the biological, psychological, and social contributors to pain.
One of the most important contributions of modern physiotherapy to chronic pain management is pain neuroscience education. PNE involves teaching patients about how pain works at a neurological level — explaining concepts such as central sensitization, the role of the brain in producing pain, and why pain does not always equal tissue damage. Systematic reviews and meta-analyses consistently demonstrate that PNE produces clinically meaningful improvements in pain catastrophizing, fear of movement, and disability, particularly when combined with active interventions such as exercise or manual therapy (Louw et al., 2016; Watson et al., 2019).
Physiotherapists use graded activity programs to help patients systematically and safely increase their physical activity levels despite ongoing pain. This approach is based on the principle that avoidance of movement perpetuates the cycle of deconditioning, fear, and disability. Graded exposure takes this further by specifically targeting feared movements or activities, helping patients learn through direct experience that these movements are safe.
Exercise is arguably the single most evidence-supported intervention for persistent pain. Regular physical activity triggers a cascade of beneficial neurological and physiological effects: release of endogenous opioids and endocannabinoids, reduced systemic inflammation, improved sleep quality, enhanced mood through serotonin and dopamine regulation, and beneficial neuroplastic changes in the brain.
A structured aerobic exercise program is a cornerstone of persistent pain management. Options include walking, cycling, swimming, or any enjoyable activity. Current guidelines recommend building toward 150 minutes of moderate-intensity aerobic activity per week.
Progressive resistance training addresses muscle weakness and physical deconditioning. Programs are individualized and gradually increased over time, building confidence and demonstrating that the body is capable and resilient.
While not a standalone treatment for persistent pain, manual therapy can serve as a valuable adjunct to active interventions, providing short-term pain relief that facilitates engagement with exercise and movement programs.
Pacing involves learning to balance activity and rest to avoid the "boom-bust" cycle common in persistent pain, establishing consistent, sustainable activity levels that gradually increase over time.
Mindfulness-based stress reduction and other relaxation techniques help patients develop a different relationship with their pain. Physiotherapists may incorporate breathing exercises, body scans, progressive muscle relaxation, and guided imagery into treatment programs.
The ultimate goal of physiotherapy for persistent pain is to equip individuals with the knowledge, skills, and confidence to manage their condition independently. Key strategies include:
Absolutely not. Persistent pain is a real neurological condition involving measurable changes in how the nervous system processes information. While the brain plays a central role in all pain experiences, this does not make the pain imaginary.
Not necessarily. The goal of a comprehensive physiotherapy-led approach is to reduce reliance on medication by addressing the underlying mechanisms through movement, education, and self-management strategies.
It is normal to experience some temporary increase in pain when beginning or progressing an exercise program. This does not indicate harm. Your physiotherapist will help you start at an appropriate level and progress gradually.
Most patients benefit from a structured program of 8 to 16 weeks, with ongoing self-management thereafter. Improvement is typically gradual, with gains in function and confidence often preceding reductions in pain intensity.
In most cases, no. Avoiding activities because of pain often leads to deconditioning and worsening symptoms. Your physiotherapist will help you determine which activities are safe and how to modify them if needed.
Imaging is often not necessary for persistent pain and can sometimes increase anxiety. Many structural findings on imaging are normal age-related changes found in people with no pain at all.
Living with persistent pain can feel isolating and overwhelming, but effective treatment is available. At Vaughan Physiotherapy, our team takes a comprehensive, evidence-based approach combining pain neuroscience education, graded exercise therapy, manual therapy, and self-management strategies to help you regain control of your life.
You do not have to live at the mercy of persistent pain. Contact Vaughan Physiotherapy today to book your initial assessment. Call us at (905) 832-9888 or book online at vaughanphysiotherapy.com.
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