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Human arterial responses to isometric exercise: the role of the muscle metaboreflex
Author(s) -
Davies Thomas,
Campbell Ross,
Frenneaux Michael,
White Michael
Publication year - 2006
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.20.4.a767-a
Subject(s) - isometric exercise , medicine , cardiology , pulse wave velocity , arterial stiffness , dilator , blood pressure
Exercise elicits a local augmentation in arterial distensibility, as characterised by a decrease in pulse wave velocity (PWV). This arterial response may be attributed to changes in vascular tone resulting from a systemic net constrictor response and a local dilator response to exercise. We sought to further examine this relationship, with particular reference to the muscle metaboreflex, in the local and systemic arterial response to isometric exercise. Seven healthy volunteers performed 2 minutes of isometric ankle plantar‐flexion at 40% MVC, in conjunction with 2 minutes of either non‐ischemic isometric handgrip (HG, control condition) or ischemic handgrip (IHG) at 40% MVC. IHG was followed by 2 minutes of post exercise circulatory occlusion (PECO) to maintain muscle metaboreflex activation. PWV in the exercised or contra‐lateral femoral artery was measured at baseline and immediately following exercise. BP and HR were measured continuously throughout. In the HG condition exercised leg PWV significantly decreased after exercise from 5.6 to 4.9m/s (P<0.05), whereas non‐exercised leg PWV did not change from its pre‐exercise value (5.6 to 5.9m/s, P=NS). PECO caused a sustained increase in BP but not HR. Following IHG contra‐lateral leg PWV significantly increased during PECO from 5.7 to 6.6m/s (P<0.05), whereas exercised leg PWV did not change from its pre‐exercised value (5.8 to 5.9m/s, P=NS). Sustained muscle metaboreflex activation causes a systemic stiffening of the arterial tree, which can abolish the normal post‐exercise decrease in PWV seen in an exercised limb.