The infection is over. Your tests "are normal." But you never went back to being who you were: energy runs out before the day does, yesterday's effort sends today the bill, and your mind feels covered in fog.
This has a name, a scientific definition and an investigative path.
What Long COVID actually is
The World Health Organization defines Long COVID as the continuation or development of new symptoms three months after SARS-CoV-2 infection, lasting at least two months, with no other diagnostic explanation.
The most frequent symptoms in the literature:
- Fatigue, disproportionate and persistent
- Post-exertional malaise: significant worsening after physical or mental activity
- Sleep disturbances and non-restorative sleep
- Shortness of breath and exercise intolerance
- Brain fog: difficulty with concentration and memory
- Palpitations and dizziness, especially when standing
Why it happens — what science is investigating
Long COVID is not a mystery without clues. The main lines of evidence point to mechanisms that can coexist:
- Immune system dysfunction and persistent low-grade inflammation
- Dysautonomia: dysregulation of the autonomic nervous system, which controls heart rate, blood pressure and digestion — frequently as POTS
- Mast cell activation, with allergy-like, multisystem symptoms
- Microvascular and tissue perfusion changes
- Viral persistence or viral fragments in some tissues
That is why treating Long COVID as "just tiredness" or "just anxiety" fails: the condition is multisystemic and demands a matching investigation.
The most common mistake: normal basic tests = discharge
A normal blood count, TSH and vitamin D do not rule out Long COVID. Proper investigation considers the detailed history, the symptom pattern (especially post-exertional malaise), sleep assessment, autonomic testing when indicated, and screening for comorbidities the infection may have triggered — such as dysautonomia and mast cell activation.
What you can record before your consultation
- Timeline: when the infection happened, when each symptom appeared
- What worsens and what relieves symptoms (exertion, heat, food, stress)
- Sleep pattern and energy levels throughout the day
- Resting and standing heart rate, if you can measure them
These data turn an appointment into an investigation.
Your symptoms are real. Science already recognizes this — and correct investigation starts with taking you seriously.