@article{ca3d55c0803a11df928f000ea68e967b,
title = "Autonomic control of heart rate by metabolically sensitive skeletal muscle afferents in humans",
abstract = "Isolated activation of metabolically sensitive skeletal muscle afferents (muscle metaboreflex) using post-exercise ischaemia (PEI) following handgrip partially maintains exercise-induced increases in arterial blood pressure (BP) and muscle sympathetic nerve activity (SNA), while heart rate (HR) declines towards resting values. Although masking of metaboreflex-mediated increases in cardiac SNA by parasympathetic reactivation during PEI has been suggested, this has not been directly tested in humans. In nine male subjects (23 ± 5 years) the muscle metaboreflex was activated by PEI following moderate (PEI-M) and high (PEI-H) intensity isometric handgrip performed at 25% and 40% maximum voluntary contraction, under control (no drug), parasympathetic blockade (glycopyrrolate) and β-adrenergic blockade (metoprolol or propranalol) conditions, while beat-to-beat HR and BP were continuously measured. During control PEI-M, HR was slightly elevated from rest (+3 ± 2 beats min-1); however, this HR elevation was abolished with β-adrenergic blockade (P < 0.05 vs. control) but augmented with parasympathetic blockade (+8 ± 2 beats min-1, P < 0.05 vs. control and β-adrenergic blockade). The HR elevation during control PEI-H (+9 ± 3 beats min-1) was greater than with PEI-M (P < 0.05), and was also attenuated with β-adrenergic blockade (+4 ± 2 beats min-1, P < 0.05 vs. control), but was unchanged with parasympathetic blockade (+9 ± 2 beats min-1, P > 0.05 vs. control). BP was similarly increased from rest during PEI-M and further elevated during PEI-H (P < 0.05) in all conditions. Collectively, these findings suggest that the muscle metaboreflex increases cardiac SNA during PEI in humans; however, it requires a robust muscle metaboreflex activation to offset the influence of cardiac parasympathetic reactivation on heart rate.",
author = "Fisher, {James P} and Thomas Seifert and Doreen Hartwich and Young, {Colin N} and Secher, {Niels H} and Fadel, {Paul J} and Fisher, {James P} and Thomas Seifert and Doreen Hartwich and Young, {Colin N} and Secher, {Niels H} and Fadel, {Paul J}",
year = "2010",
month = apr,
day = "1",
doi = "10.1113/jphysiol.2009.185470",
language = "English",
volume = "588",
pages = "1117--27",
journal = "European Respiratory Journal",
issn = "0903-1936",
publisher = "European Respiratory Society",
number = "Pt 7",
}