Persistent Exertional Dyspnea and Perceived Exercise Intolerance After Mild COVID-19: A Critical Role for Breathing Dysregulation?
Esther L van Voorthuizen, Hanneke A C van Helvoort, Jeanette B Peters and 2 others
PMID 35900016WHAT IT FOUND
In 21 patients with unexplained breathlessness after mild COVID-19, 20 showed signs of breathing dysregulation on exercise testing.
Their heart and lung function were normal, suggesting the symptoms stem from how they breathe rather than physical deconditioning or organ damage.
Key findings
0120 of the 21 patients demonstrated abnormalities in resting blood gases, ventilatory efficiency, or breathing patterns consistent with breathing dysregulation.
02Cardiopulmonary exercise testing showed normal aerobic capacity and no evidence of cardiovascular or gas exchange problems, arguing against deconditioning as the primary cause.
03More than half of the patients displayed a constant, non-increasing end-tidal CO2 during exercise, a pattern specific for hyperventilation syndrome.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
Small sample size of 21 patients limits generalizability. Lack of a control group makes it impossible to definitively attribute findings to COVID-19 specifically versus other post-infectious states. Respiratory muscle strength was not systematically assessed, so weakness cannot be fully ruled out. The study did not measure skeletal muscle mitochondrial function or systemic oxygen extraction, leaving peripheral muscle contributions unclear. Retrospective design relies on available clinical data rather than a predefined protocol.
Declared interests
None reported.
The easy way to misread this
Do not conclude that breathing dysregulation is the sole cause of symptoms. The study could not rule out respiratory muscle weakness or peripheral muscle metabolic abnormalities, and the small sample size without controls means these findings suggest a hypothesis rather than prove a specific post-COVID mechanism.