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Updated: Jun 3, 2026

Investigation into Deep Breathing through Measurement of Ventilatory Parameters and Observation of Breathing Patterns
Published on: September 16, 2019
Profound hyperventilation and development of periodic breathing during exceptional orthostatic stress in a
Joseph Donnelly1, Samuel J E Lucas, Kate N Thomas
1Department of Physiology, University of Otago, Dunedin, New Zealand. donjo492@student.otago.ac.nz
Abstract:
In this case report we describe a trial of experimentally induced syncope in a healthy young volunteer that produced abnormal periods of hyperventilation (V(A)=57 L/min) and periodic breathing; the latter persisting for approximately 60 min following termination of the trial. In this example, independent of systemic hypotension, the severe hyperventilation and related hypocapnia (end-tidal PET(CO2)) induced by orthostatic stress (lower body negative pressure) resulted in a ∼65% reduction in cerebral blood flow velocity. Potential mechanisms underlying these striking cardiorespiratory patterns are discussed.
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