title: Heart-rate response to sympathetic nervous stimulation, exercise, and magnesium concentration in various sleep conditions.
abstract: The aim of this study was to clarify the mechanism of impaired exercise tolerance in chronic sleep-restricted conditions by investigating variables related to heart-rate (HR) response to sympathetic nervous stimulation. Sixteen healthy men (mean age 21.5 years) were tested in a control state, acute sleep-loss state, and chronic sleep-restricted state. Participants underwent cardiopulmonary exercise testing in each state. Their norepinephrine (NE) concentration was measured before and immediately after exercise. Intracellular magnesium (Mg) concentration was measured in a resting state. Exercise duration was shorter and the ratio of HR response to the percentage increase in NE was higher in the chronic sleep-restricted state than in the control state. Intracellular Mg gradually decreased from control to chronic sleep restriction. There was a negative correlation between peak exercise duration and the ratios of HR response to the rate of increase in NE. Intracellular Mg was positively correlated with the ratios of HR response to the increase in NE both in control and in acute sleep loss. The authors conclude that the impaired exercise tolerance in a chronic sleep-restricted state is caused by hypersensitivity of the HR response to sympathetic nervous stimulation, which showed a compensation for decreased intracellular Mg concentration.
authors.affiliation: Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki, Japan.
authors.forename: Kazuto
authors.initials: K
authors.lastname: Omiya
authors.forename: Yoshihiro J
authors.initials: YJ
authors.lastname: Akashi
authors.forename: Kihei
authors.initials: K
authors.lastname: Yoneyama
authors.forename: Naohiko
authors.initials: N
authors.lastname: Osada
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tanabe
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Miyake
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D012890:Sleep / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D055815:Young Adult
chemical_list: D008274:Magnesium; D009638:Norepinephrine