"I am exhausted no matter how much I sleep" is one of the most common sentences in primary care. Fatigue is a symptom—not a diagnosis. A structured workup often finds treatable causes; sometimes the label is myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or long COVID, requiring specialised pacing and support.
Common medical causes to rule out
- Hypothyroidism—cold intolerance, weight gain, dry skin
- Iron deficiency / anemia—heavy periods, breathlessness, pale skin
- Sleep apnea—snoring, morning headaches, daytime sleepiness
- Diabetes and liver/kidney disease—picked up on blood tests
- Depression and anxiety—often overlap with physical fatigue
- Vitamin B12, folate, vitamin D—context-dependent testing
ME/CFS and post-viral fatigue
ME/CFS is defined by prolonged fatigue plus post-exertional worsening, unrefreshing sleep, and cognitive or orthostatic symptoms—after other causes are considered. Management focuses on pacing, not aggressive graded exercise that crashes patients.
A sensible evaluation path
Clinicians usually take history, examine, and order targeted labs (CBC, ferritin, TSH, glucose, etc.) and consider sleep study if apnea is suspected. Keep a two-week symptom and sleep diary before appointments.
Questions to ask your doctor
- Which blood tests should we start with for my fatigue?
- Could my medicines or sleep habits explain this?
- Should I be screened for sleep apnea?
- When is ME/CFS or long COVID considered?
- What pacing or rehab programmes are evidence-based?
Trusted references
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Educational content from DoctorBookly Editorial. Not personal medical advice. Always consult a licensed clinician for diagnosis, treatment, and emergencies.
