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Human sinus arrhythmia as an index of vagal cardiac outflowThe human central vagal mechanisms were investigated by measuring the intervals between heartbeats during controlled breathing (at breathing intervals of 2.5-10 s and nominal tidal volumes of 1000 and 1500 ml) in six young men and women. It was found that as the breathing interval increased, the longest heart periods became longer, the shortest heart periods became shorter, and the peak-valley P-P intervals increased asymptotically. Peak-valley intervals also increased in proportion to tidal volume, although this influence was small. The phase angles between heart period changes and respiration were found to vary as linear functions of breathing interval. Heart period shortening began in inspiration at short breathing intervals and in expiration at long breathing intervals, while heart period lengthening began in early expiration at all breathing intervals studied. It is concluded that a close relationship exists between variations of respiratory depth and interval and the quantity, periodicity, and timing of vagal cardiac outflow in conscious humans. The results indicate that at usual breathing rates, phasic respiration-related changes of vagal motoneuron activity begin in expiration, progress slowly, and are incompletely expressed at fast breathing ratges.
Document ID
19830049280
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Eckberg, D. L.
(U.S. Veterans Administration, Medical Center; Virginia Medical College, Richmond VA, United States)
Date Acquired
August 11, 2013
Publication Date
April 1, 1983
Publication Information
Publication: Journal of Applied Physiology: Respiratory, Environmental and Exercise Physiology
Volume: 54
ISSN: 0161-7567
Subject Category
Aerospace Medicine
Accession Number
83A30498
Funding Number(s)
CONTRACT_GRANT: NIH-HL-22581
CONTRACT_GRANT: NAG9-14
CONTRACT_GRANT: NIH-HL-22296
CONTRACT_GRANT: NIH-HL-22546
Distribution Limits
Public
Copyright
Other

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