Sensitivity of the human ventilatory response to muscle metaboreflex activation during concurrent mild hypercapnia

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Sensitivity of the human ventilatory response to muscle metaboreflex activation during concurrent mild hypercapnia. / Alghaith, Jassim; Balanos, George; Eves, Francis; White, Michael.

In: Experimental Physiology, Vol. 104, No. 3, 01.03.2019, p. 359–367.

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@article{34dc7be16fc340fba0cc15198e5b3872,
title = "Sensitivity of the human ventilatory response to muscle metaboreflex activation during concurrent mild hypercapnia",
abstract = "New Findings: What is the central question of this study? What is the relationship between the level of systemic hypercapnia and the magnitude of the additional hyperpnoea produced in response to a standardized level of muscle metaboreflex activation? What is the main finding and its importance? When a standardized activation of the muscle metaboreflex was combined with exposure to increasing levels of hypercapnia, the hyperpnoea this caused increased linearly. The concept of a synergistic interaction between the muscle metaboreflex and the central chemoreflex in humans is supported by this finding. Abstract: Ventilation increases during muscle metaboreflex activation when postexercise circulatory occlusion (PECO) traps metabolites in resting human muscle, but only in conditions of concurrent systemic hypercapnia. We hypothesize that a linear relationship exists between the level of hypercapnia and the magnitude of the additional hyperpnoea produced in response to a standardized level of muscle metaboreflex activation. Fifteen male subjects performed four trials, in which the end-tidal partial pressure of carbon dioxide ((Formula presented.)) was elevated by 1, 3, 7 or 10 mmHg above resting values using a dynamic end-tidal forcing system. In each trial, subjects were seated in an isometric dynamometer designed to measure ankle plantar flexor force. Rest for 2 min in room air was followed by 15 min of exposure to one of the four levels of hypercapnia, at which 5 min further rest was followed by 2 min of sustained isometric calf muscle contraction at 50% of predetermined maximal voluntary strength. Immediately before cessation of exercise, a cuff around the upper leg was inflated to a suprasystolic pressure to cause PECO for 3 min, before its deflation and a further 5 min of rest, concluding exposure to hypercapnia. The PECO consistently elevated mean arterial blood pressure by ∼10 mmHg in all trials, indicating similar levels of metaboreflex activation. Increased ventilation during PECO was related to (Formula presented.) as described by the following linear regression equation: Change in minute ventilation (l min −1) = 0.85 × (Formula presented.) (mmHg) + 0.80 (l min −1). This finding supports our hypothesis and furthers the idea of a synergistic interaction between muscle metaboreflex activation and central chemoreflex stimulation. ",
keywords = "hypercapnia, hyperpnoea, metaboreflex",
author = "Jassim Alghaith and George Balanos and Francis Eves and Michael White",
note = "Alghaith JM, Balanos GM, Eves FF, White MJ. Sensitivity of the human ventilatory response to muscle metaboreflex activation during concurrent mild hypercapnia. Exp. Physiol. 2018;1–9. https://doi.org/10.1113/EP087224",
year = "2019",
month = mar,
day = "1",
doi = "10.1113/EP087224",
language = "English",
volume = "104",
pages = "359–367",
journal = "Experimental Physiology",
issn = "0958-0670",
publisher = "Wiley",
number = "3",

}

RIS

TY - JOUR

T1 - Sensitivity of the human ventilatory response to muscle metaboreflex activation during concurrent mild hypercapnia

AU - Alghaith, Jassim

AU - Balanos, George

AU - Eves, Francis

AU - White, Michael

N1 - Alghaith JM, Balanos GM, Eves FF, White MJ. Sensitivity of the human ventilatory response to muscle metaboreflex activation during concurrent mild hypercapnia. Exp. Physiol. 2018;1–9. https://doi.org/10.1113/EP087224

PY - 2019/3/1

Y1 - 2019/3/1

N2 - New Findings: What is the central question of this study? What is the relationship between the level of systemic hypercapnia and the magnitude of the additional hyperpnoea produced in response to a standardized level of muscle metaboreflex activation? What is the main finding and its importance? When a standardized activation of the muscle metaboreflex was combined with exposure to increasing levels of hypercapnia, the hyperpnoea this caused increased linearly. The concept of a synergistic interaction between the muscle metaboreflex and the central chemoreflex in humans is supported by this finding. Abstract: Ventilation increases during muscle metaboreflex activation when postexercise circulatory occlusion (PECO) traps metabolites in resting human muscle, but only in conditions of concurrent systemic hypercapnia. We hypothesize that a linear relationship exists between the level of hypercapnia and the magnitude of the additional hyperpnoea produced in response to a standardized level of muscle metaboreflex activation. Fifteen male subjects performed four trials, in which the end-tidal partial pressure of carbon dioxide ((Formula presented.)) was elevated by 1, 3, 7 or 10 mmHg above resting values using a dynamic end-tidal forcing system. In each trial, subjects were seated in an isometric dynamometer designed to measure ankle plantar flexor force. Rest for 2 min in room air was followed by 15 min of exposure to one of the four levels of hypercapnia, at which 5 min further rest was followed by 2 min of sustained isometric calf muscle contraction at 50% of predetermined maximal voluntary strength. Immediately before cessation of exercise, a cuff around the upper leg was inflated to a suprasystolic pressure to cause PECO for 3 min, before its deflation and a further 5 min of rest, concluding exposure to hypercapnia. The PECO consistently elevated mean arterial blood pressure by ∼10 mmHg in all trials, indicating similar levels of metaboreflex activation. Increased ventilation during PECO was related to (Formula presented.) as described by the following linear regression equation: Change in minute ventilation (l min −1) = 0.85 × (Formula presented.) (mmHg) + 0.80 (l min −1). This finding supports our hypothesis and furthers the idea of a synergistic interaction between muscle metaboreflex activation and central chemoreflex stimulation.

AB - New Findings: What is the central question of this study? What is the relationship between the level of systemic hypercapnia and the magnitude of the additional hyperpnoea produced in response to a standardized level of muscle metaboreflex activation? What is the main finding and its importance? When a standardized activation of the muscle metaboreflex was combined with exposure to increasing levels of hypercapnia, the hyperpnoea this caused increased linearly. The concept of a synergistic interaction between the muscle metaboreflex and the central chemoreflex in humans is supported by this finding. Abstract: Ventilation increases during muscle metaboreflex activation when postexercise circulatory occlusion (PECO) traps metabolites in resting human muscle, but only in conditions of concurrent systemic hypercapnia. We hypothesize that a linear relationship exists between the level of hypercapnia and the magnitude of the additional hyperpnoea produced in response to a standardized level of muscle metaboreflex activation. Fifteen male subjects performed four trials, in which the end-tidal partial pressure of carbon dioxide ((Formula presented.)) was elevated by 1, 3, 7 or 10 mmHg above resting values using a dynamic end-tidal forcing system. In each trial, subjects were seated in an isometric dynamometer designed to measure ankle plantar flexor force. Rest for 2 min in room air was followed by 15 min of exposure to one of the four levels of hypercapnia, at which 5 min further rest was followed by 2 min of sustained isometric calf muscle contraction at 50% of predetermined maximal voluntary strength. Immediately before cessation of exercise, a cuff around the upper leg was inflated to a suprasystolic pressure to cause PECO for 3 min, before its deflation and a further 5 min of rest, concluding exposure to hypercapnia. The PECO consistently elevated mean arterial blood pressure by ∼10 mmHg in all trials, indicating similar levels of metaboreflex activation. Increased ventilation during PECO was related to (Formula presented.) as described by the following linear regression equation: Change in minute ventilation (l min −1) = 0.85 × (Formula presented.) (mmHg) + 0.80 (l min −1). This finding supports our hypothesis and furthers the idea of a synergistic interaction between muscle metaboreflex activation and central chemoreflex stimulation.

KW - hypercapnia

KW - hyperpnoea

KW - metaboreflex

UR - http://www.scopus.com/inward/record.url?scp=85061011242&partnerID=8YFLogxK

U2 - 10.1113/EP087224

DO - 10.1113/EP087224

M3 - Article

VL - 104

SP - 359

EP - 367

JO - Experimental Physiology

JF - Experimental Physiology

SN - 0958-0670

IS - 3

ER -