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The ventilatory response to muscle metaboreflex stimulation during concurrent hypercapnia
Author(s) -
Bruce Richard Michael,
White Michael John
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.702.7
Subject(s) - hypercapnia , medicine , anesthesia , isometric exercise , cuff , respiratory minute volume , cardiorespiratory fitness , ventilation (architecture) , cardiology , respiratory system , surgery , mechanical engineering , engineering
The role of skeletal muscle metaboreceptive afferents in human cardiorespiratory control can be examined using post exercise circulatory occlusion (PECO). We have shown that PECO produces ventilatory responses in humans, but only during concurrent hypercapnia and now aim to determine if this interaction is caused by a central or peripheral mechanism. This was achieved by measuring ventilatory and cardiovascular responses to PECO during either systemic hypercapnia (systemic trial) or during local hypercapnia (trapped in the muscle; local trial) respectively. With Ethical Committee approval, 10 males performed 2 trials. Using a cuff inflated to 200mmHg around the right thigh and the inhalation a normoxic hypercapnic gas mixture, manoeuvres were performed to achieve either a systemic or local hypercapnia. In both trials participants then rested for 2min followed by a 1.5min isometric plantarflexion exercise with subsequent PECO for 3.5min before thigh cuff deflation. We found that PECO maintained blood pressure at exercising levels in both trials, suggesting activation of metaboreceptive afferent but ventilation was only maintained at exercising levels in the systemic trial (+6 l.min‐1). These results suggest that ventilatory responses induced by muscle metaboreceptive afferent feedback during concurrent hypercapnia are unrelated to muscle hypercapnia but a central interaction is indicated.