The Spectrum of Long COVID Cardiac Symptoms
Cardiovascular symptoms are among the most common and distressing manifestations of long COVID, affecting an estimated 20–30% of people with persistent post-COVID symptoms. The spectrum includes heart palpitations (the most common complaint), chest pain, shortness of breath on exertion, exercise intolerance, and in some cases, documented cardiac abnormalities including myocarditis and pericarditis.
Understanding which mechanism is driving symptoms in a given patient is critical, because the mechanisms are different and require different management approaches.
POTS: The Most Common Mechanism
Postural orthostatic tachycardia syndrome (POTS) is a form of dysautonomia — dysfunction of the autonomic nervous system — characterised by an abnormal increase in heart rate (≥30 beats per minute) when moving from lying to standing. It produces palpitations, dizziness, brain fog, and fatigue that are worse when upright and better when lying down.
POTS is estimated to affect 2–14% of long COVID patients, making it one of the most common long COVID diagnoses. The mechanism involves SARS-CoV-2 damage to the autonomic nervous system — either direct viral injury to autonomic ganglia, or autoimmune damage mediated by antibodies targeting adrenergic receptors. A 2021 study found autoantibodies against alpha and beta adrenergic receptors in 67% of long COVID patients with POTS symptoms.
Management of long COVID POTS includes increased salt and fluid intake (to expand blood volume), compression garments, graduated exercise rehabilitation (starting with recumbent exercise), and in some cases, medications including fludrocortisone, midodrine, or beta-blockers.
Myocarditis and Pericarditis
Myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the pericardial sac surrounding the heart) occur in a minority of COVID-19 patients — estimated at 1–4% of hospitalised patients and lower in non-hospitalised cases. A 2021 study using cardiac MRI found evidence of myocardial inflammation in 60% of recovered COVID-19 patients at 2–3 months post-infection — though many had no symptoms.
Most cases of COVID-19-related myocarditis resolve within 3–6 months. Management includes rest (avoiding strenuous exercise during the inflammatory phase), anti-inflammatory medications, and cardiac monitoring. Return to exercise should be gradual and guided by symptom resolution and cardiac imaging.
What Helps: The Evidence Base
For POTS specifically, the most evidence-based interventions are: increased sodium intake (10–12g/day), increased fluid intake (2–3L/day), compression garments, and a structured exercise rehabilitation programme starting with recumbent exercise (rowing, swimming, recumbent cycling) before progressing to upright exercise.
For the underlying autonomic dysfunction, emerging evidence supports several approaches: low-dose naltrexone (which reduces neuroinflammation), antihistamines (which address mast cell activation that frequently co-occurs with POTS), and — with preliminary evidence — lion's mane mushroom (which supports nerve regeneration through NGF stimulation and may help repair autonomic nerve damage).
Cordyceps mushroom has shown evidence for improving cardiovascular function and exercise tolerance in people with reduced aerobic capacity — which may be relevant for long COVID patients with exercise intolerance, though direct evidence in this population is limited.