Details

Autor(en) / Beteiligte

• Cooke, William H
• Cox, James F
• Diedrich, Andre M
• Taylor, J. Andrew
• Beightol, Larry A
• Ames, James E., IV
• Hoag, Jeffrey B
• Seidel, Henrik
• Eckberg, Dwain L

Titel

Controlled breathing protocols probe human autonomic cardiovascular rhythms

Ist Teil von

• American journal of physiology. Heart and circulatory physiology, 1998-02, Vol.274 (2), p.H709-H718

Ort / Verlag

United States

Erscheinungsjahr

1998

Quelle

EZB-FREE-00999 freely available EZB journals

Beschreibungen/Notizen

• 1  Departments of Medicine, Physiology, and Mathematical Sciences, Medical College of Virginia of Virginia Commonwealth University, and Hunter Holmes McGuire Department of Veterans Affairs Medical Center, Richmond, Virginia 23249; 3  Hebrew Rehabilitation Center for the Aged, Brookline, Massachusetts 02167; 2  Deutsche Forschungsanstalt für Luft- und Raumfahrt, Institute of Aerospace Medicine, Cologne 51147; and 4  Institute for Theoretical Physics, University of Berlin, Berlin D-10623, Germany The purpose of this study was to determine how breathing protocols requiring varying degrees of control affect cardiovascular dynamics. We measured inspiratory volume, end-tidal CO 2 , R-R interval, and arterial pressure spectral power in 10 volunteers who followed the following 5 breathing protocols: 1 ) uncontrolled breathing for 5 min; 2 ) stepwise frequency breathing (at 0.3, 0.25, 0.2, 0.15, 0.1, and 0.05 Hz for 2 min each); 3 ) stepwise frequency breathing as above, but with prescribed tidal volumes; 4 ) random-frequency breathing (~0.5-0.05 Hz) for 6 min; and 5 ) fixed-frequency breathing (0.25 Hz) for 5 min. During stepwise breathing, R-R interval and arterial pressure spectral power increased as breathing frequency decreased. Control of inspired volume reduced R-R interval spectral power during 0.1 Hz breathing ( P  < 0.05). Stepwise and random-breathing protocols yielded comparable coherence and transfer functions between respiration and R-R intervals and systolic pressure and R-R intervals. Random- and fixed-frequency breathing reduced end-tidal CO 2 modestly ( P  < 0.05). Our data suggest that stringent tidal volume control attenuates low-frequency R-R interval oscillations and that fixed- and random-rate breathing may decrease CO 2 chemoreceptor stimulation. We conclude that autonomic rhythms measured during different breathing protocols have much in common but that a stepwise protocol without stringent control of inspired volume may allow for the most efficient assessment of short-term respiratory-mediated autonomic oscillations. respiratory sinus arrhythmia; power spectra; R-R interval