Document Detail


The independently fractal nature of respiration and heart rate during exercise under normobaric and hyperbaric conditions.
MedLine Citation:
PMID:  15705537     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To test the hypothesis that the fractal character of breathing and heart rate are independent, inter-breath intervals (IBI) and R-R intervals (RRI) were measured during rest and two levels of exercise at 1 and 2.8 ATA in a hyperbaric chamber in 18 male and female subjects (ages 19-74 years). Both RRI and IBI showed fractal properties. Fractal dimensions (D) for IBI were (mean +/- S.D.) 1.33 +/- 0.11, 1.29 +/- 0.12, 1.19 +/- 0.16 (rest, light and heavy exercise at 1ATA); 1.33 +/- 0.13, 1.25 +/- 0.13, 1.18 +/- 0.14 (same conditions at 2.8 ATA). Corresponding D for RRI were 1.19 +/- 0.11, 1.05 +/- 0.07 and 1.02 +/- 0.05 (1ATA); 1.20 +/- 0.10, 1.03 +/- 0.04 and 1.01 +/- 0.02 (2.8 ATA). The fractal dimension of each variable decreased with exercise and was unaffected by hyperbaric exposure. These two systems were not cross-correlated under any of the six conditions. During rest and light and moderate exercise at 1 and 2.8 ATA the results are consistent with heart rate variability and breathing rate variability being mutually independent of one another.
Authors:
Bruce J West; Lori A Griffin; Heather J Frederick; Richard E Moon
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  145     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-02-11     Completed Date:  2005-05-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  219-33     Citation Subset:  IM    
Affiliation:
Mathematics Division, Army Research Office, Research Triangle Park, NC, and Physics Department, Duke University, Durham, NC, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Atmospheric Pressure
Cross-Over Studies
Electrocardiography / methods
Exercise / physiology*
Female
Fractals*
Heart Rate / physiology*
Humans
Hyperbaric Oxygenation*
Male
Middle Aged
Models, Statistical
Nonlinear Dynamics
Oxygen Consumption
Physical Endurance
Respiration*
Rest / physiology
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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