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Relationship between changes in pulmonary V ˙ O 2 kinetics and autonomic regulation of blood flow.
MedLine Citation:
PMID:  23347008     Owner:  NLM     Status:  Publisher    
Various regulatory mechanisms of pulmonary oxygen uptake ( V ˙ O 2 ) kinetics have been postulated. The purpose of this study was to investigate the relationship between vagal withdrawal, measured using RMSSDRR, the root mean square of successive differences in cardiac interval (RR) kinetics, a mediator of oxygen delivery, and V ˙ O 2 kinetics. Forty-nine healthy adults (23 ± 3 years; 72 ± 13 kg; 1.80 ± 0.08 m) performed multiple repeat transitions to moderate- and heavy-intensity exercise. Electrocardiography, impedance cardiography, and pulmonary gas exchange parameters were measured throughout; time domain measures of heart rate variability were subsequently derived. The parameters describing the dynamic response of V ˙ O 2 , cardiac output ( Q ˙ ) and RMSSDRR were determined using a mono-exponential model. During heavy-intensity exercise, the phase II τ of V ˙ O 2 was significantly correlated with the τ of RR (r = 0.36, P < 0.05), Q (r = 0.67, P < 0.05), and RMSSDRR (r = 0.38, P < 0.05). The τ describing the rise in Q explained 47% of the variation in V ˙ O 2 τ, with 30% of the rate of this rise in Q explained by the τ of RR and RMSSDRR. No relationship was evident between V ˙ O 2 kinetics and those of Q, RR, or RMSSDRR during moderate exercise. Vagal withdrawal kinetics support the concept of a centrally mediated oxygen delivery limitation partly regulating V ˙ O 2 kinetics during heavy-, but not moderate-, intensity exercise.
M A McNarry; M I C Kingsley; M J Lewis
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-24
Journal Detail:
Title:  Scandinavian journal of medicine & science in sports     Volume:  -     ISSN:  1600-0838     ISO Abbreviation:  Scand J Med Sci Sports     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-25     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9111504     Medline TA:  Scand J Med Sci Sports     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2013 John Wiley & Sons A/S.
College of Engineering, Swansea University, Wales, UK.
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