In patients with hypertension, volitional slowing of the respiratory rate has been purported to reduce arterial pressure via withdrawal of sympathetic tone. We examined the effects of paced breathing at 7, 14, and 21 breaths/min, with reciprocal changes in tidal volume, on muscle sympathetic nerve activity, forearm blood flow, forearm vascular conductance, and blood pressure in 21 men and women, 8 of whom had modest elevations in systemic arterial pressure. These alterations in breathing frequency and volume did not affect steady-state levels of sympathetic activity, blood flow, vascular conductance, or blood pressure (all P > 0.05), even though they had the expected effect on sympathetic activity within breaths (i.e., increased modulation during low-frequency/high-tidal volume breathing) (P < 0.001). These findings were consistent across subjects with widely varied baseline levels of sympathetic activity (4-fold), mean arterial pressure (78-110 mmHg), and vascular conductance (15-fold), and those who became hypocapnic during paced breathing vs. those who maintained normocapnia. These findings challenge the notion that slow, deep breathing lowers arterial pressure by suppressing steady-state sympathetic outflow.
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http://dx.doi.org/10.1152/ajpheart.00112.2013 | DOI Listing |
J Neuroophthalmol
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Ophthalmology Department (AC-C, MF-R, SA-A, RA, BS-D), Seu Maternitat, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, Spain; Faculty of Medicine and Health Sciences (AC-C, SA-A, BS-D), Universitat de Barcelona, Barcelona, Spain; Fundació Per La Recerca Biomèdica-IDIBAPS (MF-R, SA-A, BS-D), Barcelona, Spain; and Ophthalmology Department (MS-G), Consorci Mar Parc de Salut de Barcelona, Barcelona, Spain.
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View Article and Find Full Text PDFPLoS One
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The Research and Implementation Unit PROgrez, Department of Physiotherapy and Occupational Therapy Næstved-Slagelse-Ringsted Hospitals, Slagelse, Denmark.
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View Article and Find Full Text PDFJ Cardiovasc Transl Res
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Duke University Medical Center, Durham, NC, 27710, USA.
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Arch Toxicol
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Chemical and Environmental Toxicology Program, Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, K1N 6N5, Canada.
Hypertension or high blood pressure (BP) is a prevalent and manageable chronic condition which is a significant contributor to the total global disease burden. Environmental chemicals, including mercury (Hg), may contribute to hypertension onset and development. Hg is a global health concern, listed by the World Health Organization (WHO) as a top ten chemical of public health concern.
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