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Cardiac Baroreflex Control in Humans During and Immediately After Brief Exposure to Simulated High Altitude by Frédéric Roche; Claire Reynaud; Martin Garet; Vincent Pichot; Frédéric Costes; Jean‐Claude Barthélémy is a Medicine article available to read on EtoBox.

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## Summary To examine the baroreflex response in humans during and immediately after __acute hypoxia__ exposure, the cardiac baroreflex sensitivity (BRS) was studied using adaptation of RR intervals in response to spontaneous systolic blood pressure fluctuations (sequences methodology) in 11 unacclimatized subjects. All measurements were made under fixed breathing rate, and realized consecutively at baseline level (20 min), at an inspired oxygen concentration of 11% (15 min) and again under normoxic conditions (20 min; recovery period). The spontaneous baroreflex response decreases progressively during hypoxic exposure, causing a tachycardic response at this FiO~2~ without any significant alteration of the systolic or diastolic blood pressure. The magnitude of decrease for this variable at the end of exposure averaged 42·9 ± 15·6%. The simultaneous spectral analysis of heart rate (HR) variability in hypoxic condition confirmed an alteration in the parasympathetic activity (HFnu: −17·8 ± 30·9% versus basal conditions, __P__<0·01) counterbalanced by an exaggerated sympathetic activity (LFnu: +33 ± 42·4%, __P__<0·05) at the sinus node. Interestingly, we could observe an enhanced cardi

Who reads Cardiac Baroreflex Control in Humans During and Immediately After Brief Exposure to Simulated High Altitude?

Author

Frédéric Roche; Claire Reynaud; Martin Garet; Vincent Pichot; Frédéric Costes; Jean‐Claude Barthélémy

Publisher

John Wiley and Sons; Wiley (Blackwell Publishing); Blackwell Publishing Inc.; Wiley (ISSN 0144-5979)

Published

2002

Language

EN

Field

Medicine (Health Sciences)