Performance Area > Peer Reviewed Studies Discussion
Sleep, Biological Rhythms, & Stress - its effect on performance
adarqui:
Effects of dehydration on isometric muscular strength and endurance.
Applied Sciences
Medicine & Science in Sports & Exercise. 30(2):284-288, February 1998.
GREIWE, JEFFREY S.; STAFFEY, KIMBERLY S.; MELROSE, DONALD R.; NARVE, MURIEL D.; KNOWLTON, RONALD G.
Abstract:
To examine the effects of rapid dehydration on isometric muscular strength and endurance, seven men were tested at baseline (control) and after a dehydration (dHST) and a euhydration (eHST) heat stress trial. The dHST consisted of intermittent sauna exposure until 4% of body mass was lost, whereas the eHST consisted of intermittent sauna exposure (same duration as dHST) with water replacement. Peak torque was determined for the knee extensors and elbow flexors during three isometric maximal voluntary contractions. Time to fatigue was determined by holding a maximal voluntary contraction until torque dropped below 50% peak torque for 5 s. Strength and endurance were assessed 3.5 h after the HSTs (no food or water intake). Body mass was decreased 3.8 +/- 0.4% post dHST and 0.4 +/- 0.3% post eHST. Plasma volume was decreased 7.5 +/- 4.6% and 5.7 +/- 4.4%, 60 and 120 min post dHST, respectively. A small (1.6 mEq[middle dot]L-1) but significant increase was found for serum Na+ concentration 60 min post dHST but had returned to predehydration level 120 min post dHST. Serum K+ and myoglobin concentrations were not affected by HSTs. Peak torque was not different (P > 0.05) among control, dHST, and eHST for the knee extensors (Mean (Nm) +/- SD, 285 +/- 79, 311 +/- 113, and 297 +/- 79) and elbow flexors (79 +/- 12, 83 +/- 15, and 80+/- 12). Time to fatigue was not different (P > 0.05) among control, dHST and eHST for the knee extensors (Mean (s) +/- SD, 42.4+/- 11.5, 45.3 +/- 7.6, and 41.8 +/- 6.0) and elbow flexors(48.2 +/- 8.9, 44.0 +/- 9.4, and 46.0 +/- 6.4). These results provide evidence that isometric strength and endurance are unaffected 3.5 h after dehydration of approximately 4% body mass.
Sleep deprivation induced anxiety and anaerobic performance
The aim of this study was to investigate the effects of sleep
deprivation induced anxiety on anaerobic performance. Thirteen
volunteer male physical education students completed the Turk-
ish version of State Anxiety Inventory and performed Wingate
anaerobic test for three times: (1) following a full-night of habit-
ual sleep (baseline measurements), (2) following 30 hours of
sleep deprivation, and (3) following partial-night sleep depriva-
tion. Baseline measurements were performed the day before
total sleep deprivation. Measurements following partial sleep
deprivation were made 2 weeks later than total sleep deprivation
measurements. State anxiety was measured prior to each Win-
gate test. The mean state anxiety following total sleep depriva-
tion was higher than the baseline measurement (44.9 ± 12.9 vs.
27.6 ± 4.2, respectively, p = 0.02) whereas anaerobic perform-
ance parameters remained unchanged. Neither anaerobic pa-
rameters nor state anxiety levels were affected by one night
partial sleep deprivation. Our results suggest that 30 hours con-
tinuous wakefulness may increase anxiety level without impair-
ing anaerobic performance, whereas one night of partial sleep
deprivation was ineffective on both state anxiety and anaerobic
performance.
The role of a short post-lunch nap in improving cognitive, motor, and sprint performance in participants with partial sleep deprivation
The aim of this study was to determine the effects of a post-lunch nap on subjective alertness and performance following partial sleep loss. Ten healthy males (mean age 23.3 years, s = 3.4) either napped or sat quietly from 13:00 to 13:30 h after a night of shortened sleep (sleep 23:00 - 03:00 h only). Thirty minutes after the afternoon nap or control (no-nap) condition, alertness, short-term memory, intra-aural temperature, heart rate, choice reaction time, grip strength, and times for 2-m and 20-m sprints were recorded. The afternoon nap lowered heart rate and intra-aural temperature. Alertness, sleepiness, short-term memory, and accuracy at the 8-choice reaction time test were improved by napping (P < 0.05), but mean reaction times and grip strength were not affected (P > 0.05). Sprint times were improved. Mean time for the 2-m sprints fell from 1.060 s (s(x)macr = 0.018) to 1.019 s (s(x)macr = 0.019) (P = 0.031 paired t-test); mean time for the 20-m sprints fell from 3.971 s (s(x)macr = 0.054) to 3.878 s (s(x)macr = 0.047) (P = 0.013). These results indicate that a post-lunch nap improves alertness and aspects of mental and physical performance following partial sleep loss, and have implications for athletes with restricted sleep during training or before competition.
Effects of One Night of Partial Sleep Deprivation upon Diurnal Rhythms of Accuracy and Consistency in Throwing Darts
Authors: Benjamin J. Edwards a; Jim Waterhouse a
Affiliation: a Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
DOI: 10.1080/07420520902929037
Publication Frequency: 8 issues per year
Published in: journal Chronobiology International, Volume 26, Issue 4 May 2009 , pages 756 - 768
Subjects: Biological Rhythms; Physiology;
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Abstract
Sixty subjects were tested five times per waking day on two occasions for accuracy and reliability in throwing 20 darts at a target. Two experimental conditions were investigated: following a normal nocturnal sleep (7-8 h sleep, normal) and after having retired to bed 4 h later than normal the previous night but rising at the normal time (3-4 h sleep, sleep deprivation). Sublingual (core) temperature and subjective estimates of alertness and fatigue were measured in all sessions. Performance at throwing darts was assessed by three methods: mean distance of the dart from the bulls-eye; number of times the target was missed; and variability of the scores from the darts thrown. There was no evidence that performance was affected by physical fatigue arising during the course of throwing the 20 darts. All variables showed significant diurnal rhythms, those of alertness and performance being phased over 1 h earlier than core temperature, and that of fatigue over 1 h earlier than the inverse of temperature. Core temperature was not affected by sleep deprivation, but all other variables showed significant changes, indicative of mood and performance decrement. Increasing time awake was associated with decreased alertness and increased fatigue, as well as slight negative effects upon performance. We conclude that the simple task of throwing darts at a target provides information about chronobiological changes in circumstances where time awake and sleep loss might affect psychomotor performance.
Keywords: Circadian rhythms; Psychomotor performance; Time awake
Effects of a selective sleep deprivation on subsequent anaerobic performance
The aim of the study was to investigate the effects of a partial sleep deprivation on a subsequent supramaximal exercise evaluated from the 30 second Wingate test, and on the following recovery. To take into account the active muscle mass, the Wingate test was performed against a constant braking force related to the data of a force-velocity test conducted on a Monark cycle ergometer (Model 814 E with weights) one week before the experimental test. Eight highly trained athletes were enrolled for this study. The changes in ventilatory and metabolic responses were analyzed during and upon completion of physical 30 second exercise, taking place after two nights, in other words, after a reference night and after a night with reduced sleep. Partial sleep deprivation was obtained by delaying bedtime until 3 a.m. The 30 second Wingate test was performed between 9 a.m. and noon the following days, using a Monark ergometer (Model 814 E). The analyses of change scores disclosed that there were no main significant effects for measures of ventilation, lactates and pHV levels under the two experimental conditions. The peak power, the mean power output and the peak velocity recorded after partial sleep deprivation were not modified in comparison with the values obtained after the reference night. These findings suggest that acute sleep loss did not contribute to alterations in supramaximal exercise.
Sleep deprivation and exercise
Sleep deprivation can be defined as total or partial suppress of sleep and is associated with alterations in endocrine, metabolic, physical, cognitive functions and modifications of the sleep patterns that compromise health and quality of life. Physical exercise is associated with improvement of cardiovascular, respiratory, muscular, endocrine and nervous system, and a better sleep quality. However, the association of these two conditions is unclear, partly due to the difficulty to obtain volunteers to participate in this type of protocol with no financial compensation. The majority of the studies which investigate the association between physical exercises and sleep deprivation focus on aerobic performance and verify little or no effect of this parameter. Concerning anaerobic power and strength, significant alterations have not been found; however, for prolonged events there may be an interaction between these two factors, which suggests a protection mechanism. Nevertheless, it is important to consider that one of the main alterations caused by sleep deprivation the increase of the subjective perception, which presents a factor to decrease and compromise the physical performance per se, and may represent a masking element of the deleterious effects of sleep deprivation. Thus, the aim of present review is to discuss the different aspects of relationship between physical exercise and sleep deprivation, showing their effects and consequences in physical performance.
The Impact of Sleep Deprivation on Decision Making: A Review
Few sleep deprivation (SD) studies involve realism or high-level decision making, factors relevant to
managers, military commanders, and so forth, who are undergoing prolonged work during crises. Instead,
research has favored simple tasks sensitive to SD mostly because of their dull monotony. In contrast,
complex rule-based, convergent, and logical tasks ate unaffected by short-term SD, seemingly because
of heightened participant interest and compensatory effort. However, recent findings show that despite
this effort, SD still impairs decision making involving the unexpected, innovation, revising plans,
competing distraction, and effective communication. Decision-making models developed outside SD
provide useful perspectives on these latter effects, as does a neuropsychological explanation of sleep
function. SD presents particular difficulties for sleep-deprived decision makers who require these latter
skills during emergency situations.
The Acute Effects of Twenty-Four Hours of Sleep Loss on the Performance of National-Caliber Male Collegiate Weightlifters
Blumert, P.A., A.J. Crum, M. Ernsting, J.S. Volek, D.B. Hollander, E.E. Haff, and G.G. Haff. The acute effects of twenty-four hours of sleep loss on the performance of national-caliber male collegiate weightlifters. J. Strength Cond. Res. 21(4):1146–1154. 2007.—Currently, the degree to which sleep loss influences weightlifting performance is unknown. This study compared the effects of 24 hours of sleep loss on weightlifting performance and subjective ratings of psychological states pre-exercise and postexercise in national-caliber male collegiate weightlifters. Nine males performed a maximal weightlifting protocol following 24 hours of sleep loss and a night of normal sleep. The subjects participated in a randomized, counterbalanced design with each sleep condition separated by 7 days. Testosterone and cortisol levels were quantified prior to, immediately after, and 1 hour after the resistance training session. Additionally, profile of mood states and subjective sleepiness were evaluated at the same time points. The resistance training protocol consisted of several sets of snatches, clean and jerks, and front squats. Performance was evaluated as individual exercise volume load, training intensity and overall workout volume load, and training intensity. During each training session the maximum weight lifted for the snatch, clean and jerk, and front squat were noted. No significant differences were found for any of the performance variables. A significant decrease following the sleep condition was noted for cortisol concentration immediately after and 1 hour postexercise. Vigor, fatigue, confusion, total mood disturbance, and sleepiness were all significantly altered by sleep loss. These data suggest that 24 hours of sleep loss has no adverse effects on weightlifting performance. If an athlete is in an acute period of sleep loss, as noticed by negative mood disturbances, it may be more beneficial to focus on the psychological (motivation) rather than the physiological aspect of the sport.
Caffeine: Implications for Alertness in Athletes
Caffeine is one of the most widely consumed drugs in the world, taken socially and for its alertness- and performance-promoting actions. Extensive reports assert that caffeine increases alertness and cognitive performance levels and, when taken before exercise, demonstrates ergogenic properties. Caffeine ingestion has been associated with increased performance during endurance submaximal, and acute, high-intensity exercise. The exact mechanism of action for the performance effects of caffeine is unknown, although several physiologically and psychologically based theories exist as to how caffeine achieves increased performance capabilities. This paper outlines the known sites of caffeine activity in the body,and discusses these with respect to the effects of caffeine observed during performance assessments.
Effect of sleep deprivation on tolerance of prolonged exercise
Summary Acute loss of sleep produces few apparent physiological effects at rest. Nevertheless, many anecdotes suggest that adequate sleep is essential for optimum endurance athletic performance. To investigate this question, heavy exercise performance after 36 h without sleep was compared with that after normal sleep in eight subjects. During prolonged treadmill walking at about 80% of the $$\dot V_{O_2 } $$ max, sleep loss reduced work time to exhaustion by an average of 11% (p=0.05). This decrease occurred despite doubling monetary incentives for subjects during work after sleeplessness. Subjects appeared to fall into “resistant” and “susceptible” categories: four showed less than a 5% change in performance after sleep loss, while four others showed decrements in exercise tolerance ranging from 15 to 40%. During the walk, sleep loss resulted in significantly greater perceived exertion (p<0.05), even though exercise heart rate and metabolic rate ( $$\dot V_{O_2 } $$ and $$\dot V_{CO_2 } $$ ) were unchanged. Minute ventilation was significantly elevated during exercise after sleep loss (p<0.05). Sleep loss failed to alter the continuous slow rises in $$\dot V_E $$ E and heart rate that occurred as work was prolonged. These findings suggest that the psychological effects of acute sleep loss may contribute to decreased tolerance of prolonged heavy exercise.
Sleep deprivation and cardiorespiratory function
Influence of intermittent submaximal exercise
Journal European Journal of Applied Physiology and Occupational Physiology
Publisher Springer Berlin / Heidelberg
ISSN 0301-5548 (Print) 1439-6327 (Online)
Issue Volume 56, Number 3 / May, 1987
DOI 10.1007/BF00690902
Pages 338-344
SpringerLink Date Sunday, December 12, 2004
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Sleep deprivation and cardiorespiratory function
Influence of intermittent submaximal exercise
M. J. Plyley1, R. J. Shephard1 Contact Information, G. M. Davis1 and R. C. Goode1
(1) School of Physical and Health Education, University of Toronto, M5S 1A1 Toronto, Ontario, Canada
Accepted: 24 November 1986
Summary The effects of 64 h of sleep deprivation upon cardiorespiratory function was studied in 11 young men ( $$\dot V_{{\text{O}}_{{\text{ 2 max}}} } = 55.5{\text{ ml kg}}^{ - 1} {\text{ min}}^{ - 1} ,{\text{ STPD}}$$ ). Six subjects engaged in normal sedentary activities, while the others walked on a treadmill at 28% $$\dot V_{{\text{O}}_{{\text{ 2 max}}} } $$ for one hour in every three; eight weeks later, sleep deprivation was repeated with a crossover of subjects. Immediate post-deprivation measurement of $$\dot V_{{\text{O}}_{{\text{ 2 max}}} } $$ showed a small but statistically significant decrease (–3.8 ml min–1 kg–1, STPD), with no difference between exercise and control trials. The final decrement in aerobic power was not due to a loss of motivation, as 88% (21 of 24) of post-deprivation tests still showed a plateau of $$\dot V_{{\text{O}}_{{\text{ 2 max}}} } $$ ; in addition, terminal heart rates (198 vs 195 beats min–1), respiratory exchange ratios (1.14 vs 1.15) and blood lactate levels (12.1 vs 11.8 mmol l–1) were not significantly different after sleep deprivation. The decrease in $$\dot V_{{\text{O}}_{{\text{ 2 max}}} } $$ was associated with a lower $$\dot V_{{\text{E}}_{{\text{ 2 max}}} } $$ (127 vs 142 l min–1, BTPS) and a substantial haemodilution (13%). Physiological responses to sub-maximal exercise showed persistence of the normal diurnal rhythm in heart rate and oxygen consumption, with no added effects due to sleep deprivation. However, ratings of perceived exertion (Borg scale) increased significantly throughout sleep deprivation. The findings are consistent with a mild respiratory acidosis, secondary to reduced cortical arousal and/or a progressive depletion of tissue glycogen stores which are not altered appreciably by moderate physical activity.
Multiple Effects of Caffeine on Simulated High-Intensity Team-Sport Performance.
Applied Sciences
Medicine & Science in Sports & Exercise. 37(11):1998-2005, November 2005.
STUART, GENE R. 1; HOPKINS, WILL G. 1; COOK, CHRISTIAN 2; CAIRNS, SIMEON P. 1
Abstract:
Introduction: Caffeine enhances performance of single bouts of endurance exercise, but its effects on repeated bouts typical of those in high-intensity team sports are unclear.
Purpose: To investigate effects of caffeine in a performance test simulating physical and skill demands of a rugby union game.
Methods: The study was a double-blind, randomized, crossover design in which nine competitive male rugby players ingested either caffeine (6 mg[middle dot]kg-1 body mass) or placebo (dextrose) 70 min before performing a rugby test. Each test consisted of seven circuits in each of two 40-min halves with a 10-min half-time rest. Each circuit included stations for measurement of sprint time (two straight-line and three agility sprints), power generation in two consecutive drives, and accuracy for passing balls rapidly. Interstitial fluid was sampled transdermally by electrosonophoresis before ingestion of caffeine or placebo and then before testing, at half-time, and immediately after testing; samples were assayed chromatographically for caffeine and epinephrine concentrations.
Results: The effects of caffeine on mean performance (+/-90% confidence limits) over all 14 circuits were: sprint speeds, 0.5% (+/-1.7%) through 2.9% (+/-1.3%); first-drive power, 5.0% (+/-2.5%); second-drive power, -1.2% (+/-6.8%); and passing accuracy, 9.6% (+/-6.1%). The enhancements were mediated partly through a reduction of fatigue that developed throughout the test and partly by enhanced performance for some measures from the first circuit. Caffeine produced a 51% (+/-11%) increase in mean epinephrine concentration; correlations between individual changes in epinephrine concentration and changes in performance were mostly unclear, but there were some strong positive correlations with sprint speeds and a strong negative correlation with passing accuracy.
Conclusion: Caffeine is likely to produce substantial enhancement of several aspects of high-intensity team-sport performance.
Elevations in core and muscle temperature impairs repeated sprint performance
B. Drust 1 , P. Rasmussen 2 , M. Mohr 2 , B. Nielsen 2 and L. Nybo 2
1 Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
2 Institute of Exercise and Sport Sciences, August Krogh Institute, University of Copenhagen, Copenhagen, Denmark
Correspondence to B Drust, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Henry Cotton Campus, Webster Street, Liverpool L3 2ET, UK.
Copyright 2005 Scandinavian Physiological Society
KEYWORDS
fatigue • hyperthermia • muscle metabolites • sprint performance
Abstract
Abstract Methods Results Discussion References
Aim: The present study investigated the effects of hyperthermia on intermittent exercise and repeated sprint performance.
Methods: Seven men completed 40 min of intermittent cycling comprising of 15 s exercise (306 ± 22 W) and 15 s rest periods (0 W) followed by 5 × 15 s maximal sprints on a cycle ergometer in normal (?20 °C, control) and hot (40 °C, hyperthermia) environments.
Results: Completion of the intermittent protocol in the heat elevated core and muscle temperatures (39.5 ± 0.2 °C; 40.2 ± 0.4 °C), heart rate (178 ± 11 beats min?1), rating of perceived exertion (RPE) (18 ± 1) and noradrenaline (38.9 ± 13.2 ?mol l?1) (all P < 0.05). During the first sprint (n = 6), both peak and mean power output were similar across the environmental conditions. However, mean power over the last four sprints declined to a larger extent during hyperthermia compared with the control trial (P < 0.05). Consequently, average mean power output during the five sprints was lower in hyperthermia (558.0 ± 146.9 W) compared with control (617.5 ± 122.6 W; P < 0.05). Power output during the repeated sprints was reduced by hyperthermia despite an elevated muscle temperature that should promote sprint performance. Venous plasma potassium concentrations (H; 5.3 ± 0.8 mmol l?1 vs. C; 6.3 ± 1.0 mmol l?1, P = 0.06) and muscle lactate levels (H; 76.6 ± 24.3 mmol kg?1 dry weight vs. C; 108.8 ± 20.1 mmol kg?1 dry weight) were lower following the hyperthermic sprints compared to control.
Conclusion: Although an elevated muscle temperature is expected to promote sprint performance, power output during the repeated sprints was reduced by hyperthermia. The impaired performance does not seem to relate to the accumulation of recognized metabolic fatigue agents and we, therefore, suggest that it may relate to the influence of high core temperature on the function of the central nervous system.
adarqui:
Polyphasic sleep strategies improve prolonged sustained performance: A field study on 99 sailors
Author: Claudio Stampiab
Affiliations: a Human Neurosciences Research Unit, University of Ottawa, Ottawa, Canada
b University of Bologna, Italy
DOI: 10.1080/02678378908256879
Publication Frequency: 4 issues per year
Published in: journal Work & Stress, Volume 3, Issue 1 January 1989 , pages 41 - 55
Subjects: Behavioral Medicine; Health Psychology; Occupational/Industrial Health & Safety; Office & Workplace; Work & Organizational Psychology;
Formats available: PDF (English)
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Abstract
In situations where continuous prolonged work demands exist, the habitual nocturnal monophasic (6-8h duration) sleep pattern can rarely be accomplished, and performance effectiveness may sometimes be severely compromised by accumulation of sleep debt. Several studies have shown that naps can be disproportionately effective in recovering functioning during continuous work (CW).
In this study, sleep-wake patterns and their relationship to performance were studied for 99 sailors involved in solo and double-handed ocean sailing races (a model of a highly demanding CW situation). Most sailors spontaneously adopted multiple nap sleep-wake schedules and adapted without major difficulties to such polyphasic patterns. 66.5% had mean sleep episode durations (SEDs) ranging from 20 min to 2h. Overall mean Total Sleep Time (TST) per 24h was reduced from a baseline of 7.5 to 6.3h. Race performance correlated negatively and significantly with mean SEDs and TSTs. Best performance results were obtained by those sleeping for periods of between 20 min and 1 h and for a total of 4.5 to 5.5h of sleep per day.
The results are discussed together with several chronobiological, phylogenetic and experimental studies and issues, all of which suggest that adult humans may have a damped polyphasic sleep-wake tendency. It is also proposed that polyphasic sleep schedules could become promising and feasible solutions for the management of sleep requirements under prolonged CW situations.
Truck Drivers Sleep-Wake Time Arrangements
Authors: C. R. C. Moreno; L. Matuzaki; F. Carvalho; R. Alves; I. Pasqua; G. Lorenzi-Filho
DOI: 10.1076/brhm.34.2.137.14487
Publication Frequency: 6 issues per year
Published in: journal Biological Rhythm Research, Volume 34, Issue 2 April 2003 , pages 137 - 143
Subjects: Animal Physiology; Biological Rhythms; Biology; Physiology;
Formats available: PDF (English)
Previously published as: Journal of Interdisiplinary Cycle Research (0022-1945) until 1994
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Abstract
Irregular working hours, including night work, change sleep-wake time arrangements which in turn might affect the ability to drive safely. This study aims to compare the effects of an irregular and a fixed day shift system on the sleep-wake cycle of truck drivers. The investigation of sleep-wake cycle was carried-out with 37 truck drivers working on two transportation plants: 24 working on irregular working hours and 13 on fixed day shift. The truck drivers filled out sleep logs and wore actigraphs for 10 consecutive days to identify activity and rest episodes. The group working in irregular hours showed more sleep episodes per 24 h and they were shorter compared to the fixed shift group (p < 0.05). No differences were found between the two transportation plants. These results suggest an the influence of working hours on specific sleep-wake patterns. The polyphasic sleep pattern shown by irregular shift group could be a strategy to cope with sleep deprivation, which may account for their difficulty to resist falling asleep behind the wheel.
Sleep Inertia: Best Time Not to Wake Up?
Authors: Paul Naitoha; Tamsin Kellya; Harvey Babkoffb
Affiliations: a Naval Health Research Center, San Diego, California, USA
b Department of Psychology, Bar-Ilan University, Ramat-Gan, Israel
DOI: 10.3109/07420529309059699
Publication Frequency: 8 issues per year
Published in: journal Chronobiology International, Volume 10, Issue 2 April 1993 , pages 109 - 118
Subjects: Biological Rhythms; Physiology;
Formats available: PDF (English)
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Abstract
Sleep inertia is a brief period of inferior task performance and/or disori-entation immediately after sudden awakening from sleep. Normally sleep inertia lasts <5 min and has no serious impact on conducting routine jobs. This preliminary study examined whether there are best and worst times to wake up stemming from circadian effects on sleep inertia. Since the process of falling asleep is strongly influenced by circadian time, the reverse process of awakening could be similarly affected. A group of nine subjects stayed awake for a 64-h continuous work period, except for 20-min sleep periods (naps) every 6 h. Another group of 10 subjects stayed awake for 64 h without any sleep. The differences between these two groups in performance degradation are expected to show sleep inertia on the background of sleep deprivation. Sleep inertia was measured with Baddeley's logical reasoning task, which started within 1 min of awakening and lasted for 5 min. There appeared to be no specific circadian time when sleep inertia is either maximal or minimal. An extreme form of sleep inertia was observed, when the process of waking up during the period of the circadian body temperature trough became so traumatic that it created “sleep (nap) aversion.” The findings lead to the conclusion that there are no advantages realized on sleep inertia by waking up from sleep at specific times of day.
gukl:
http://onlinelibrary.wiley.com/doi/10.1111/cen.12747/full
Metabolic and hormonal effects of ‘catch-up’ sleep in men with chronic, repetitive, lifestyle-driven sleep restriction
--- Quote ---"Results
Insulin sensitivity was higher following three nights of sleep extension compared to sustained sleep restriction. Fasting insulin, c-peptide, HOMA-IR, HOMA-β, leptin and PYY decreased with ‘catch-up’ sleep, QUICKI and testosterone increased, while morning cortisol and LH did not change. Targeted acoustic stimuli reduced SWS by 23%, but did not alter insulin sensitivity.
Conclusions
Three nights of ‘catch-up’ sleep improved insulin sensitivity in men with chronic, repetitive sleep restriction. Methods to improve metabolic health by optimizing sleep are plausible."
--- End quote ---
LBSS:
oh that's really interesting. thanks gukl.
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