Causes of Chronic Fatigue: Why Am I Always Tired?

Persistent fatigue — exhaustion not relieved by adequate rest — is one of the most common complaints in primary care, accounting for 5–7% of all GP consultations. While lifestyle factors are often involved, significant fatigue lasting more than 6 weeks warrants medical investigation to exclude treatable underlying causes.

Medical causes of chronic fatigue include: iron-deficiency anemia (especially in women of reproductive age), hypothyroidism (underactive thyroid), type 2 diabetes, sleep apnea (unrefreshing sleep with snoring and daytime drowsiness), depression and anxiety, chronic kidney disease, heart failure, celiac disease, and B12 or vitamin D deficiency.

Chronic fatigue syndrome (CFS/ME) is a distinct medical condition characterized by severe fatigue lasting more than 6 months, post-exertional malaise (symptoms worsen after physical or mental activity), unrefreshing sleep, cognitive impairment ('brain fog'), and orthostatic intolerance. It affects approximately 17–24 million people worldwide.

Diagnostic workup for chronic fatigue typically includes: full blood count (CBC), thyroid function tests (TSH, free T4), fasting glucose or HbA1c, ferritin and iron studies, vitamin B12 and D levels, liver and kidney function tests, and CRP/ESR to screen for inflammatory conditions. Use AI clinical analysis to organize your symptoms before your appointment.

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