Journal ArticleDOI
Hyperbaric bradycardia and hypoventilation in exercising men: effects of ambient pressure and breathing gas
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It is concluded that heart rate control, but not ventilatory control, is sensitive to relatively small increases in hydrostatic pressure.Abstract:
We sought to determine whether hydrostatic pressure contributed to bradycardia and hypoventilation in hyperbaria. Eight men were studied during exercise at 50, 150, and 250 W while breathing 1) air...read more
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Human Physiology in an Aquatic Environment.
TL;DR: Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses.
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Pulmonary Gas Exchange in Diving
TL;DR: Diving-related pulmonary effects are due mostly to increased gas density, immersion-related increase in pulmonary blood volume, and (usually) a higher inspired Po(2), and the net result of relative hypoventilation and increased Vd/Vt is hypercapnia.
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The Clinical Significance of Relative Bradycardia.
TL;DR: The causes and incidence of relative bradycardia are reviewed in this article, where a wide variety of infectious and non-infectious diseases are found in a wide range of clinical conditions.
Journal ArticleDOI
Predictors of increased PaCO2 during immersed prone exercise at 4.7 ATA.
Anne D. Cherry,IF Forkner,HJ Frederick,Michael J. Natoli,EA Schinazi,JP Longphre,JL Conard,William D. White,John J. Freiberger,BW Stolp,Neal W. Pollock,P. O. Doar,AE Boso,EL Alford,AJ Walker,AC Ma,MA Rhodes,Richard E. Moon +17 more
TL;DR: It is concluded that the major contributors to increased Pa(CO(2)) during exercise at 4.7 ATA are increased depth and external respiratory resistance.
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A potential early physiological marker for CNS oxygen toxicity: hyperoxic hyperpnea precedes seizure in unanesthetized rats breathing hyperbaric oxygen
TL;DR: It is concluded that hyperoxic hyperpnea (Phase 3 of the compound hyperoxic ventilatory response) is a predictor of an impending seizure while breathing poikilocapnic HBO(2) at rest in unanesthetized rats.
References
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Journal ArticleDOI
Handbook of Physiology.
TL;DR: This is the first volume of the proposed many-sectioned "Handbook" in which the American Physiological Society intends to present comprehensively the entire field of physiology.
Journal ArticleDOI
Respiration-synchronous fluctuations in stroke volume, heart rate and arterial pressure in humans.
Karin Toska,M. Eriksen +1 more
TL;DR: The main source of respiratory fluctuations in MAP in supine humans is thus variation in SV, while inverse, vagally mediated HR variations tend to reduce the fluctuations in CO and MAP.
Journal ArticleDOI
Differential effects of nitrous oxide on baroreflex control of heart rate and peripheral sympathetic nerve activity in humans.
TL;DR: N2O produces activation of the sympathetic nerves directed to skeletal muscle blood vessels, and it decreases baroreflex-mediated tachycardia without diminishing barore flex-mediated augmentations in sympathetic outflow.
Journal ArticleDOI
Nitrous oxide augments sympathetic outflow: direct evidence from human peroneal nerve recordings.
Thomas J. Ebert,John P. Kampine +1 more
TL;DR: Brief exposure to 25% and 40% N2O produces striking increases in sympathetic outflow to skeletal muscle in humans, and is associated with progressive, large increases in muscle sympathetic nerve activity and forearm vascular resistance.
Journal ArticleDOI
Pulmonary mechanisms and work of breathing at maximal ventilation and raised air pressure
TL;DR: Depletion of energy stores in the inspiratory muscles contributed to limiting V during MEx at raised air pressure, and there was a shift of lung volumes in the inspiration direction with consequent reductions of inspiratory-to-expiratory flow ratios.