Long COVID and Post-Viral Syndrome: What I Look For

A viral illness is supposed to have an ending. For a meaningful number of people, it doesn't — and what follows gets described as deconditioning, anxiety, or "just take more time," none of which is a plan.

Post-viral syndromes are not new. They have been described after Epstein-Barr, influenza, Lyme disease, and SARS. COVID simply produced enough cases at once that the pattern became impossible to ignore.

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What long COVID actually means

The working definition is symptoms that continue, recur, or first appear at least three months after a SARS-CoV-2 infection, last at least two months, and are not explained by another diagnosis. Severity of the original infection does not predict who develops it. Plenty of my patients had a mild illness they barely registered.

The symptom list is long, but it clusters:

• Energy and exertion — fatigue that isn't fixed by rest, and worsening after activity
• Cognitive — word-finding trouble, slowed processing, short-term memory lapses
• Autonomic — racing heart on standing, lightheadedness, temperature dysregulation, GI changes
• Respiratory and cardiac — breathlessness, chest tightness, exercise intolerance
• Immune and inflammatory — new food or environmental reactivity, flushing, rashes

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The three patterns I screen for first

Post-exertional malaise. Symptoms that worsen twelve to seventy-two hours after physical or cognitive effort, out of proportion to what was done, with a slow recovery. This is the single most important thing to identify, because it changes management completely. If PEM is present, a graded exercise program can make someone worse.

Orthostatic intolerance. Heart rate that climbs sharply on standing, lightheadedness, fog that lifts when lying down. This is testable at home with a ten-minute stand test, and if it fits, POTS is a separate diagnosis with its own treatments — salt, fluids, compression, and in some cases medication.

Mast cell activation. New reactivity to foods, alcohol, heat, or scents that started with the infection. Flushing, hives, GI upset, and unpredictable "allergic" episodes without true allergy.

Any of the three can be treated. Naming them is most of the work.

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What I still rule out

A post-viral diagnosis doesn't excuse a thin workup. Several conditions produce the same picture and respond to treatment:

• Iron deficiency, including with a normal hemoglobin
• Thyroid disease, with antibodies when the story fits
• B12 and vitamin D deficiency
• Sleep apnea, which infection can unmask or worsen
• Anemia, kidney and liver dysfunction, glucose abnormalities
• Perimenopause and low testosterone — both commonly overlap in age
• Medication effects, particularly antihistamines and beta blockers
• Depression and anxiety, which frequently coexist and deserve treatment on their own terms

If something on that list is abnormal, we treat it and reassess. Often it helps meaningfully even when it isn't the whole story.

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What actually helps

Pacing. The core intervention when PEM is present. Work below your threshold rather than to it, split activity into short blocks, and rest before you need to. The goal is stability first, expansion later.

Autonomic support. Increased sodium and fluid intake when appropriate, compression garments, recumbent exercise, and slow position changes. Medication when the pattern warrants it.

Sleep. Post-viral sleep is often unrefreshing and fragmented. Treating apnea, managing nighttime autonomic surges, and holding a consistent schedule all move the needle.

Protein and strength, carefully. Muscle loss compounds everything. Very short, recumbent, low-intensity resistance work, well under threshold, is usually tolerable when timed sessions are kept short.

Treating the treatable overlaps. POTS and MCAS have real protocols. So do iron deficiency and thyroid disease. Most of the improvement I see comes from stacking small wins rather than finding one answer.

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What I won't tell you

I won't tell you there's a cure, and I won't sell you an expensive protocol that promises one. Recovery is real for many people and it is usually gradual, non-linear, and frustrating in the middle.

What I will do is take the history seriously, work through the differential properly, treat what's treatable, and help you build a pacing plan you can actually hold.

If your illness started with an infection and never fully ended, that history is a clinical finding. Bring it in.