Chronic Fatigue Syndrome (ME/CFS): Causes, Symptoms, and Management
Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) is a serious, debilitating condition characterised by profound fatigue that is not improved by rest, worsens with exertion, and is accompanied by a range of neurological, immunological, and autonomic symptoms. It is not the same as ordinary tiredness.
Recognising ME/CFS
The hallmark symptom of ME/CFS is post-exertional malaise (PEM) — a significant worsening of symptoms following physical or cognitive exertion, often delayed by 12–48 hours. This distinguishes ME/CFS from ordinary fatigue, where rest generally improves energy. In ME/CFS, rest provides minimal improvement and exertion causes disproportionate setback.
Other core symptoms include unrefreshing sleep (sleep that doesn't restore regardless of duration), cognitive dysfunction ('brain fog' including poor memory, word-finding difficulties, and processing slowing), orthostatic intolerance (symptoms worsening on standing), and often chronic pain.
What causes ME/CFS
ME/CFS frequently follows viral infection (post-infectious onset is documented in 60–80% of cases), with notable clusters following Epstein-Barr virus, enteroviruses, and — with emerging prominence — SARS-CoV-2 (Long COVID). The underlying mechanisms are not fully established but involve immune dysregulation, autonomic nervous system abnormalities, mitochondrial dysfunction, and possible pathogen persistence.
ME/CFS is not caused by deconditioning, psychological factors, or exercise avoidance — though these models influenced (and harmed) clinical management for decades. The condition has measurable biological correlates that validate its physiological basis.
Management
Pacing — managing energy expenditure to remain within the available energy envelope and avoid PEM — is the most evidence-based management strategy. This means identifying your threshold for symptom exacerbation and systematically staying below it, even when you feel better on a good day.
Medical management focuses on treating specific symptoms (sleep disruption, pain, orthostatic intolerance) and is best undertaken with an ME/CFS-specialist clinician. Research into disease-modifying treatments is active following the increased attention prompted by Long COVID.
If your fatigue has the characteristics of ME/CFS — particularly post-exertional malaise — our assessment will highlight this and recommend professional evaluation.
Frequently Asked Questions
What are the main symptoms of Chronic Fatigue Syndrome?
The main symptoms of Chronic Fatigue Syndrome include post-exertional malaise, unrefreshing sleep, cognitive dysfunction, orthostatic intolerance, and chronic pain.
What causes Chronic Fatigue Syndrome?
Chronic Fatigue Syndrome often follows a viral infection and is linked to immune dysregulation, autonomic nervous system abnormalities, and mitochondrial dysfunction, but it is not caused by psychological factors or deconditioning.
How can I manage Chronic Fatigue Syndrome effectively?
Effective management of Chronic Fatigue Syndrome involves pacing your activities to avoid post-exertional malaise and working with a specialist to address specific symptoms.
Is Chronic Fatigue Syndrome the same as regular tiredness?
No, Chronic Fatigue Syndrome is characterized by profound fatigue that does not improve with rest and is accompanied by other debilitating symptoms, distinguishing it from ordinary tiredness.