Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    The effect of higher ATP cost of contraction on the metabolic response to graded exercise in patients with chronic obstructive pulmonary disease

    Access Status
    Open access via publisher
    Authors
    Layec, G.
    Haseler, Luke
    Richardson, R.
    Date
    2012
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Layec, G. and Haseler, L. and Richardson, R. 2012. The effect of higher ATP cost of contraction on the metabolic response to graded exercise in patients with chronic obstructive pulmonary disease. Journal of Applied Physiology. 112 (6): pp. 1041-1048.
    Source Title
    Journal of Applied Physiology
    DOI
    10.1152/japplphysiol.00986.2011
    ISSN
    8750-7587
    URI
    http://hdl.handle.net/20.500.11937/63306
    Collection
    • Curtin Research Publications
    Abstract

    To better understand the metabolic implications of a higher ATP cost of contraction in chronic obstructive pulmonary disease (COPD), we used 31 P-magnetic resonance spectroscopy ( 31 P-MRS) to examine muscle energetics and pH in response to graded exercise. Specifically, in six patients and six well-matched healthy controls, we determined the intracellular threshold for pH (T pH ) and inorganic phosphate-to-phosphocreatine ratio (T Pi/PCr ) during progressive dynamic plantar flexion exercise with work rate expressed as both absolute and relative intensity. Patients with COPD displayed a lower peak power output (WRmax) compared with controls (controls 25 ± 4 W, COPD 15 ± 5 W, P = 0.01) while end-exercise pH (controls 6.79 ± 0.15, COPD 6.76 ± 0.21, P = 0.87) and PCr consumption (controls 82 ± 10%, COPD 70 ± 18%, P = 0.26) were similar between groups. Both T pH and T Pi/PCr occurred at a significantly lower absolute work rate in patients with COPD compared with controls (controls: 14.7 ± 2.4 W for T pH and 15.3 ± 2.4W for T Pi/PCr ; COPD: 9.7 ± 4.5W for T pH and 10.0 ± 4.6Wfor T Pi/PCr , P > 0.05), but these thresholds occurred at the same percentage of WRmax (controls: 63 ± 11% WRmax for T pH and 67 ± 18% WRmax for T Pi/PCr ; COPD: 59 ± 9% WRmax for TpH and 61 ± 12% WRmax for T Pi/PCr , P > 0.05). Indexes of mitochondrial function, the PCr recovery time constant (controls 42 ± 7 s, COPD 45 ± 11 s, P = 0.66) and the PCr resynthesis rate (controls 105 ± 21%/min, COPD 91 ± 31%/min, P = 0.43) were similar between groups. In combination, these results reveal that when energy demand is normalized to WRmax, as a consequence of higher ATP cost of contraction, patients with COPD display the same metabolic pattern as healthy subjects, suggesting that skeletal muscle energy production is well preserved in these patients.

    Related items

    Showing items related by title, author, creator and subject.

    • Burden of disease and benefits of exercise in fixed airway obstruction asthma
      Turner, Sian Elizabeth (2009)
      Background and research questions. The characterization of chronic persistent asthma in an older adult population is not well defined. This is due to the difficulties in separating the diagnosis of asthma from that of ...
    • Alcohol consumption, smoking and lifestyle characteristics for Japanese patients with chronic obstructive pulmonary disease
      Hirayama, Fumi (2008)
      This thesis investigated lifestyle characteristics including cigarette smoking, alcohol consumption, dietary supplements intake, physical activity, and urinary incontinence status for Japanese patients with chronic ...
    • Evidence that a higher ATP cost of muscular contraction contributes to the lower mechanical efficiency associated with COPD: Preliminary findings
      Layec, G.; Haseler, Luke; Hoff, J.; Richardson, R. (2011)
      Impaired metabolism in peripheral skeletal muscles potentially contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We used 31 P-magnetic resonance spectroscopy ( 31 P-MRS) to examine the ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.