Effects of different sleep restriction protocols on sleep architecture and daytime vigilance in healthy men.
TL;DR: The study showed that cumulative declines in daytime vigilance resulted from loss of total sleep time, rather than from specific stages, and underscored the reversibility of SR effects with greater amounts of sleep.
Abstract: Sleep is regulated by complex biological systems and environmental influences, neither of which is fully clarified. This study demonstrates differential effects of partial sleep deprivation (SD) on sleep architecture and psychomotor vigilance task (PVT) performance using two different protocols (sequentially) that each restricted daily sleep to 3 hours in healthy adult men. The protocols differed only in the period of sleep restriction; in one, sleep was restricted to a 3-hour block from 12:00 AM to 3:00 AM, and in the other, sleep was restricted to a block from 3:00 AM to 6:00 AM. Subjects in the earlier sleep restriction period showed a significantly lower percentage of rapid-eye-movement (REM) sleep after 4 days (17.0 vs. 25.7 %) and a longer latency to the onset of REM sleep (L-REM) after 1 day (78.8 vs. 45.5 min) than they did in the later sleep restriction period. Reaction times on PVT performance were also better (i.e. shorter) in the earlier SR period on day 4 (249.8 vs. 272 ms). These data support the view that earlier-night sleep may be more beneficial for daytime vigilance than later-night sleep. The study also showed that cumulative declines in daytime vigilance resulted from loss of total sleep time, rather than from specific stages, and underscored the reversibility of SR effects with greater amounts of sleep.
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01 Jan 2016
TL;DR: The findings suggest that appetite, SQ and food reward are influenced by sleep parameters, but these changes may not alter EI and individuals with greater sleep quality in response to SR had greater vigorous-intensity activity time and lower EI.
Abstract: ii THESIS ABSTRACT The main objective of this thesis was to examine the independent effects of sleep duration and timing on appetite, food reward and energy balance. Study 1 investigated the associations between satiety quotient (SQ) with habitual, self-reported sleep duration, quality and timing. No significant associations were noted between SQ and sleep parameters. Short-duration sleepers had a lower mean SQ vs. those with ≥7h sleep/night (P=0.04). Study 2 evaluated associations between changes in sleep duration, efficiency and timing with changes in next day food reward. Greater sleep duration and earlier wake-times were associated with greater food reward (P=0.001). However, these associations were no longer significant after controlling for elapsed time between awakening and completion of the food reward task. Study 3 examined the effects of 50% sleep restriction (SR) anchored during the first (delayed bedtime) or second (advanced wake-time) half of the night on appetite, SQ, food reward, energy intake (EI) and energy expenditure (EE). Greater appetite ratings and explicit high-fat food reward were noted following SR with an advanced wake-time vs. control and SR with a delayed bedtime (P=0.03-0.01). No difference in SQ was noted between sessions. Energy and carbohydrate intakes were greater on day 2 and over 36h in the delayed bedtime vs. control session (P=0.03). Activity EE and moderate-intensity physical activity (PA) time were greater following delayed bedtime vs. control and advanced wake-time on day 1, whereas vigorous-intensity PA time was greater following advanced wake-time vs. delayed bedtime on day 1 (P=0.01-0.04). Greater sleep quality and slow-wave sleep duration between SR sessions were associated with lower EI and increased vigorous-intensity PA time, respectively (P=0.01-0.04). Collectively, these findings suggest that appetite, SQ and food reward are influenced by sleep parameters, but these changes may not alter EI. These findings also suggest that individuals with greater sleep quality in response to SR had greater vigorous-intensity activity time and lower EI. iii ACKNOWLEDGEMENTS I would like to express my gratitude to the volunteers who participated in my thesis studies. A special thanks to the participants from Study 3 for the long hours spent in the lab. At least we got to experience the ups and downs of sleep restriction together :) I have to extend the biggest THANKS (capital letters required) to the team of students who worked alongside me for Study 3. You all spent so many hours, at the oddest times, at the lab to help me …
4 citations
01 Jan 2014
TL;DR: In the largest, most diverse healthy sample of adults studied to date under controlled laboratory conditions, sleep restriction promoted weight gain and positive energy balance, particularly in men and African Americans.
Abstract: Habitual short sleep duration is consistently associated with weight gain and increased risk for obesity. The objective of this dissertation was to elucidate how chronic sleep restriction impacts components of energy balance, namely, weight gain, energy intake, and energy expenditure. Healthy adults (21-50 y) participated in controlled isolated laboratory protocols for 14-18 days and were randomized to either an experimental condition (baseline sleep followed by sleep restriction [5 consecutive nights of 4 hours time-in-bed [TIB] per night] and recovery sleep) or control condition (no sleep restriction: 10 hours TIB per night for all nights). Sleep-restricted subjects exhibited significant weight gain, increased caloric intake, greater consumption of fat, delayed meal timing and decreased resting metabolic rate (the largest component of energy expenditure) during sleep restriction but these changes returned to baseline levels after one night of recovery sleep (12 hours TIB). Control subjects did not exhibit a significant change in weight, caloric intake or resting metabolic rate across corresponding protocol days. Notably, there were significant gender and race differences in the energy balance response to sleep restriction. Men gained more weight, increased caloric intake to a greater degree during sleep restriction and consumed a larger percentage of calories during late-night hours than women. Relative to Caucasians, African Americans consumed a comparable amount of calories during baseline and sleep restriction but exhibited marked energy expenditure deficits after baseline sleep, sleep restriction and recovery sleep, and gained more weight during the study. In the largest, most diverse healthy sample of adults studied to date under controlled laboratory conditions, sleep restriction promoted weight gain and positive energy balance. Collectively, these results highlight the importance of obtaining sufficient sleep for regulating energy balance and maintaining a healthy weight, particularly in men and African Americans. Degree Type Dissertation Degree Name Doctor of Philosophy (PhD) Graduate Group Psychology First Advisor David F. Dinges
3 citations
Cites background from "Effects of different sleep restrict..."
..., 2010) and others (Belenkey et al., 2003; Bliese et al., 2006; Cote et al., 2008, Fafrowicz et al., 2010; Rupp et al., 2009; Wu et al., 2010; Pejovic et al., 2013) assessed neurobehavioral performance during sleep restriction under ad libitum food/drink conditions....
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01 Dec 2015
TL;DR: In this article, the authors demonstrated how exposure to physical work and restricted sleep can trigger an increase in firefighters' immune and hormonal stress responses and explored psychophysiological interactions between responses, with findings that suggest when sleep restricted, firefighters show a worsening in mood which relates to elevated hormonal and immune changes.
Abstract: This research demonstrated how exposure to physical work and restricted sleep can trigger an increase in firefighters’ immune and hormonal stress responses. The work also explored psychophysiological interactions between responses, with findings that suggest when sleep restricted, firefighters’ show a worsening in mood which relates to elevated hormonal and immune changes.
2 citations
TL;DR: In this paper , the effects of sleep extension to an active recovery session (CON) on post-exercise recovery kinetics were compared among elite rugby players, and the main finding was that sleep extension could affect cognitive function positively but did not improve neuromuscular function the day after a late exercise bout.
Abstract: Background Elite rugby players experience poor sleep quality and quantity. This lack of sleep could compromise post-exercise recovery. Therefore, it appears central to encourage sleep in order to improve recovery kinetics. However, the effectiveness of an acute ergogenic strategy such as sleep extension on recovery has yet to be investigated among athletes. Aim To compare the effects of a single night of sleep extension to an active recovery session (CON) on post-exercise recovery kinetics. Methods In a randomised cross-over design, 10 male rugby union players participated in two evening training sessions (19:30) involving collision activity, 7-days apart. After each session, participants either extended their sleep to 10 hours or attended an early morning recovery session (07:30). Prior to (PRE), immediately after (POST 0 hour [h]), 14h (POST 14) and 36h (POST 36) post training, neuromuscular, perceptual and cognitive measures of fatigue were assessed. Objective sleep parameters were monitored two days before the training session and over the two-day recovery period. Results The training session induced substantial decreases in countermovement jump mean power and wellness across all time points, while heart rate recovery decreased at POST 0 in both conditions. Sleep extension resulted in greater total sleep time (effect size [90% confidence interval]: 5.35 [4.56 to 6.14]) but greater sleep fragmentation than CON (2.85 [2.00 to 3.70]). Between group differences highlight a faster recovery of cognitive performance following sleep extension (-1.53 [-2.33 to -0.74]) at POST 14, while autonomic function (-1.00 [-1.85 to -0.16]) and upper-body neuromuscular function (-0.78 [-1.65 to 0.08]) were better in CON. However, no difference in recovery status between groups was observed at POST 36. Conclusion The main finding of this study suggests that sleep extension could affect cognitive function positively but did not improve neuromuscular function the day after a late exercise bout.
1 citations
TL;DR: Although napping in simulated altitude does not appear to significantly affect cognitive performance, sex-dependent changes in cardiac autonomic modulation and respiratory pattern should be considered before napping is prescribed as a countermeasure.
Abstract: Context: The use of daytime napping as a countermeasure in sleep disturbances has been recommended but its physiological evaluation at high altitude is limited. Objective: To evaluate the neuroendocrine response to hypoxic stress during a daytime nap and its cognitive impact. Design, Subject, and Setting: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years (Clinicaltrials identifier: NCT04146857, https://clinicaltrials.gov/ct2/show/NCT04146857?cond=napping&draw=3&rank=12). Interventions: Volunteers underwent a polysomnography, hematological and cognitive evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: normobaric normoxia (NN), normobaric hypoxia at FiO2 14.7% (NH15) and 12.5% (NH13), with a washout period of 1 week between conditions. Results: Primary outcome was the interbeat period measured by the RR interval with electrocardiogram. Compared to normobaric normoxia, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p < 0.001). Sympathetic predominance was evident by heart rate variability analysis and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as erythropoietin (∼6 UI/L) and cortisol (∼100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Additionally, although sleep efficiency was preserved, polysomnography showed lesser deep sleep and REM sleep, and periodic breathing, predominantly in men. Conclusion: Although napping in simulated altitude does not appear to significantly affect cognitive performance, sex-dependent changes in cardiac autonomic modulation and respiratory pattern should be considered before napping is prescribed as a countermeasure.
1 citations
References
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Book•
01 Jan 1968
11,993 citations
TL;DR: Techniques of recording, scoring, and doubtful records are carefully considered, and Recommendations for abbreviations, types of pictorial representation, order of polygraphic tracings are suggested.
Abstract: With the vast research interest in sleep and dreams that has developed in the past 15 years, there is increasing evidence of noncomparibility of scoring of nocturnal electroencephalograph-electroculograph records from different laboratories. In 1967 a special session on scoring criteria was held at the seventh annual meeting of the Association for the Psychophysiological Study of Sleep. Under the auspices of the UCLA Brain Information, an ad hoc committee composed of some of the most active current researchers was formed in 1967 to develop a terminology and scoring system for universal use. It is the results of the labors of this group that is now published under the imprimatur of the National Institutes of Health. The presentation is beautifully clear. Techniques of recording, scoring, and doubtful records are carefully considered. Recommendations for abbreviations, types of pictorial representation, order of polygraphic tracings are suggested.
8,001 citations
"Effects of different sleep restrict..." refers background or methods in this paper
...For example, Elmenhorst et al. reported decreased non-REM (NREM) ‘lighter’ sleep stages (defined as NREM stages 1 and 2), but increased ‘deeper’ NREM sleep stages (defined as NREM stages 3 and 4) and rapid eye movement (REM) sleep in healthy males following reductions of sleep (from 8 to 5 hours)…...
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...Polysomnographic recordings were analyzed by an experienced researcher following standard scoring criteria (Rechtschaffen and Kales 1968)....
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01 Jan 1968
3,002 citations
TL;DR: It appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults, and sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.
Abstract: OBJECTIVES: To inform the debate over whether human sleep can be chronically reduced without consequences, we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation. DESIGN: The chronic sleep restriction experiment involved randomization to one of three sleep doses (4 h, 6 h, or 8 h time in bed per night), which were maintained for 14 consecutive days. The total sleep deprivation experiment involved 3 nights without sleep (0 h time in bed). Each study also involved 3 baseline (pre-deprivation) days and 3 recovery days. SETTING: Both experiments were conducted under standardized laboratory conditions with continuous behavioral, physiological and medical monitoring. PARTICIPANTS: A total of n = 48 healthy adults (ages 21-38) participated in the experiments. INTERVENTIONS: Noctumal sleep periods were restricted to 8 h, 6 h or 4 h per day for 14 days, or to 0 h for 3 days. All other sleep was prohibited. RESULTS: Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days resulted in significant cumulative, dose-dependent deficits in cognitive performance on all tasks. Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days, and did not significantly differentiate the 6 h and 4 h conditions. Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis--displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights. Comparison of chronic sleep restriction to total sleep deprivation showed that the latter resulted in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost. A statistical model revealed that, regardless of the mode of sleep deprivation, lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h (s.e. 0.73 h). CONCLUSIONS: Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation, it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults. Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits, which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign. Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses, but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions. This suggests that sleep debt is perhaps best understood as resulting in additional wakefulness that has a neurobiological "cost" which accumulates over time.
2,694 citations
"Effects of different sleep restrict..." refers background in this paper
...Other researchers proposed, however, that even mild sleep deprivation impairs cognition significantly (Banks and Dinges 2007, Belenky et al. 2003, Elmenhorst et al. 2008, Van Dongen et al. 2003)....
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01 Jan 1968
2,439 citations