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.

Does one night of partial sleep deprivation affect the evening performance during intermittent exercise in Taekwondo players?

“…Otherwise, Jarraya et al (2013) clarified that the adverse effect of the PSDEN could be explained by the absence of paradoxical sleep, which increases at the end of night to involved in the synchronization of the circadian system. On the other hand, the present findings are in disagreement with previous studies which found no modification in endurance intensive performances after SD ( Azboy and Kaygisiz, 2009 ; Chen, 1991 ; Goodman et al, 1989 ; Mejri et al, 2014c ; Mougin et al, 1991 ; Oliver et al, 2009 ; Omiya et al, 2009 ; Racinais et al, 2004 ). These contradictory results could be explain by the differences in fitness level of participants, durations and intensities of the exercise (i.e., continuous exercise, submaximal, or maximal exercise until exhaustion, intermittent exercise), time-of-day of measurements (i.e., morning, afternoon, evening), as well as types and durations of SD (i.e., TSD, PSD in the beginning, the middle, or the end of night).…”

“…The present findings showed that no change was spotted in HR peak and RPE in responses to YYIRT following the two types of PSD. These results are well in agreement with other published investigations which revealed that did not change exercise HR ( Azboy and Kaygisiz, 2009 ; Chen, 1991 ; Goodman et al, 1989 ; Martin and Chen, 1984 ; Martin and Gaddis, 1981 ; Meney et al, 1998 ; Mejri et al, 2014c ; Oliver et al, 2009 ; Omiya et al, 2009 ; Plyley et al, 1987 ; Ricardo et al, 2009 ) and RPE ( Meney et al, 1998 ; Mejri et al, 2014c ; Oliver et al, 2009 ). This last result affirmed the hypothesis that RPE is normally closely related to HR ( Borg, 1971 ).…”

“…In previous studies, the effects of SD on endurance intensive performances was examined after submaximal ( Martin and Chen, 1984 ; Mougin et al, 1991 ; Mougin et al, 2001 ; Oliver et al, 2009 ; Ricardo et al, 2009 ), maximal ( Azboy and Kaygisiz, 2009 ; Chen, 1991 ; Goodman et al, 1989 ; Martin and Chen, 1984 ; Mougin et al, 1991 ; Mougin et al, 2001 ; Mejri et al, 2014c ; Oliver et al, 2009 ; Omiya et al, 2009 ; Plyley et al, 1987 ; Racinais et al, 2004 ; Ricardo et al, 2009 ) exercise. However, conflicting findings were observed and that could be mainly attributed to differences in exercise protocols, participants’ fitness, experimental environment, and certainly, durations of the SD.…”

“…However, in aerobic performance previous investigations reported a decrease ( Azboy and Kaygisiz, 2009 ; Chen, 1991 ; Oliver et al, 2009 ; Plyley et al, 1987 ; Ricardo et al, 2009 ), or no modification ( Azboy and Kaygisiz, 2009 ; Chen, 1991 ; Goodman et al, 1989 ; Oliver et al, 2009 ; Racinais et al, 2004 ) after a total sleep deprivation (TSD) which is almost never occurred in athletes despite that just few studies ( Mougin et al, 1991 ; Mougin et al, 2001 ; Omiya et al, 2009 ) have investigated the effects of PSD on aerobic performance, and reported contradictory findings. The discrepancy observed in earlier studies could be explain by the differences in populations, duration of SD, and the performance assessment protocols as mention Racinais et al (2004) .…”

Magnesium in the Central Nervous System

“…In rats, Mg deficiency is associated with an increased amplitude in daily variation of sleep and slow--wave sleep delta power, and has been noted to shorten life span and lower reproductive ability (Chollet et al, 2001;Motta et al, 1998). In humans, chronic sleep deprivation is associated with progressively decreasing levels of intra--cellular Mg, reduced duration of cardio--pulmonary exercise and increased hyper--sensitivity of the chronotropic response to sympathetic nervous stimulation (Omiya et al, 2009). Intriguingly, Mg depletion is associated with decreased melatonin and its supple--mentation alleviates the symptoms (Billyard et al, 2006;Depoortere et al, 1993;.…”