Symptom cluster
Cardiopulmonary symptoms
Breathlessness, chest tightness, and exercise limits, often when standard heart and lung tests read normal. This page covers: Dyspnea / breathlessness, Chest pain / palpitations, Incident cardiovascular events (1-year elevated risk), Exercise intolerance / reduced VO2.
What causes it
The leading explanations, each with its evidence grade and audit status.
Dysautonomia / autonomic dysfunction produces Dyspnea / breathlessness.
fibrinaloid microclots">fibrinaloid microclots">Fibrinaloid microclots / coagulopathy produces Dyspnea / breathlessness.
Endothelial dysfunction produces Incident cardiovascular events (1-year elevated risk).
Mitochondrial / metabolic dysfunction produces Exercise intolerance / reduced VO2.
Deconditioning (as cause) contested-cause Exercise intolerance / reduced VO2.
Dysautonomia / autonomic dysfunction produces Exercise intolerance / reduced VO2.
What has been tried
No treatment is approved. Each row shows how strong the evidence is, what it was measured on, and any safety or conflict flag.
Breathing retraining / physiotherapy (breathing pattern disorder) relieves Dyspnea / breathlessness.
Treat the substrate (POTS, dysautonomia) + cardiac surveillance manages Chest pain / palpitations.
Pyridostigmine improves Exercise intolerance / reduced VO2.
Recumbent / supine-biased rehabilitation (PEM-bounded) manages Exercise intolerance / reduced VO2.
How it is measured
Invasive CPET (iCPET) diagnoses Exercise intolerance / reduced VO2.
Cardiovascular event risk carries paired relative and absolute framing, and a VA-cohort generalizability note, so the numbers are not read out of context.