Normal Night Of Sleep Research Articles

Three consecutive nights of sleep loss: Effects of morning caffeine consumption on subjective sleepiness/alertness, reaction time and simulated driving performance

Caffeinated products are often consumed as a popular countermeasure to the effects of sleep loss. However, the efficacy of caffeine to exert these effects after consecutive nights of sleep loss is poorly understood. The aim of this study was to investigate the effects of three consecutive nights of restricted sleep and morning caffeine consumption on subjective ratings of sleepiness/alertness, reaction time, and simulated driving performance. Twenty healthy, habitual caffeine consumers (11 females; age: 23.3 ± 5.7 y; BMI: 22.3 ± 3.5 kg⋅m−2; caffeine intake: 204 ± 89 mg⋅day−1; Mean ± SD) who had normal sleeping patterns (≥8 h⋅night−1) participated in this double-blind, placebo-controlled, randomised study. Following one night of normal sleep (≥8 h time in bed (TIB)), participants underwent three consecutive nights of restricted sleep (5 h TIB). Participants received caffeine (200 mg; n = 10) or placebo (n = 10) capsules each morning and all participants received caffeine (100 mg) capsules each afternoon. Subjective ratings of alertness, concentration and tiredness were measured before and 1 h after morning capsule administration. Choice Reaction Time (CRT) was examined 1 h after morning capsule administration, with response speed and accuracy as outcome variables. Driving performance was assessed using a 30 min simulated driving task, with lateral (standard deviation of lane position [SDLP]; total number of line crossings [LC]) and longitudinal (standard deviation of speed [SDSP]) measures of vehicle control as outcome variables. Alertness and concentration significantly decreased, and tiredness increased across the three days of sleep loss. Caffeine only marginally alleviated these effects. No differences were observed between treatments or across trial days for response speed and accuracy on the CRT task. Likewise, no significant differences were observed between groups or across trial days for any measures of simulated driving performance. Overall, results from this study indicate that three consecutive days of sleep loss influence subjective ratings of alertness, concentration and tiredness, but does not alter CRT or simulated driving performance. Caffeine may alleviate some of the negative subjective effects imposed by restricted sleep, but the efficacy of caffeine to attenuate performance changes in CRT and driving performance were unable to be observed.

Improved Physical Performance and Decreased Muscular and Oxidative Damage With Postlunch Napping After Partial Sleep Deprivation in Athletes.

To investigate the effects of napping after partial sleep deprivation (PSD) on reaction time, mood, and biochemical response to repeated-sprint exercise in athletes. Nine male judokas performed 4 test sessions in a counterbalanced and randomized order. Participants accomplished 1 control session after a normal sleep night (NSN) and 3 after PSD with (1)no nap, (2)∼20-min nap (N20), and (3)∼90-min nap (N90) opportunities. Test sessions included the running-based anaerobic sprint test, reaction time, Hooper index, and Epworth Sleepiness Scale. Muscle-damage biomarkers and antioxidant status were evaluated before and after exercise. PSD decreased maximum (P < .001, d = 1.12), mean (P < .001, d = 1.33), and minimum (P < .001, d = 1.15) powers compared with NSN. However, N20 and N90 enhanced maximum power compared with PSD (P < .05, d = 0.54; P < .001, d = 1.06, respectively). Minimum power and mean power increased only after N90 (P < .001, d = 1.63; P < .001, d = 1.16, respectively). Epworth Sleepiness Scale increased after PSD (P < .001, d = 0.86) and decreased after N20 (P < .001, d = 1.36) and N90 (P < .001, d = 2.07). N20 reduced multiple-choice reaction time (P < .001, d = 0.61). Despite performance decrement, PSD increased postexercise aspartate aminotransferase (P < .001, d = 4.16) and decreased glutathione peroxidase (P < .001, d = 4.02) compared with NSN. However, the highest performances after N90 were accompanied with lesser aspartate aminotransferase (P < .001, d = 1.74) and higher glutathione peroxidase (P < .001, d = 0.86) compared with PSD. Napping could be preventive against performance degradation caused by sleep loss. A short nap opportunity could be more beneficial when the subsequent effort is brief and requires frequent decision making. However, a longer nap opportunity could be preventive against muscle and oxidative damage, even for higher performances.

High-Frequency Repetitive Transcranial Magnetic Stimulation Could Improve Impaired Working Memory Induced by Sleep Deprivation.

Objective To investigate whether and how the working memory impairment induced by sleep deprivation (SD) could be recovered by using repetitive transcranial magnetic stimulation (rTMS), as well as to clarify the corresponding brain activity changes. Methods Seventeen healthy adults received one session of 5.0 Hz rTMS over the left dorsolateral prefrontal cortex (DLPFC) following 24 hours of SD. Resting state functional magnetic resonance imaging (fMRI) and working memory test were performed during a rested waking period, after SD and rTMS. The amplitude of low-frequency fluctuations (ALFF) was used to detect the spontaneous neural activity changes after both SD and rTMS. The relationship between ALFF and the performance of working memory was also assessed by using correlation analysis. Results After SD, the participants exhibited lower response accuracies and longer reaction times on the working memory tests of letters and numbers. The decreased response accuracy of numbers was significantly improved after rTMS similarly to the state of the rested waking period after a normal night of sleep. ALFF values decreased from the rested waking period state to the state of SD in the brain regions involving the frontal gyrus, precuneus, angular gyrus, and parietal lobe which showed significantly increased ALFF after rTMS. Furthermore, significantly positive correlations were observed between changes of response accuracy and the changes of ALFF value of the inferior frontal gyrus and supramarginal gyrus. Conclusion These results indicate that high-frequency rTMS applied over left DLPFC may contribute to the recovery of the impaired working memory after SD by modulating the neural activity of related brain regions.

Three consecutive nights of restricted sleep: effects of morning caffeine consumption on mood, reaction time and simulated driving performance

Introduction: Sleep is a fundamental biological requirement, essential for optimal health. Individuals unable to achieve adequate amounts of sleep may experience a range of negative behavioural and psychological consequences (e.g. increased daytime sleepiness, altered mood, reduced cognitive performance, driving impairment). Caffeinated products are often consumed as a popular countermeasure to reduce sleepiness, enhance mood, and improve cognitive functioning. However, the efficacy of caffeine to exert these effects after consecutive nights of restricted sleep is poorly understood, particularly in relation to performance on complex applied tasks (e.g. driving a motor vehicle). Therefore, the aim of this study was to investigate the effects of three consecutive nights of restricted sleep on subjective ratings of mood, cognitive function, and simulated driving performance and assess the ability of a morning dose of caffeine to attenuate any effects associated with sleep restriction. Materials and methods: Twenty healthy habitual caffeine consumers (11 females; age: 23.3±5.7 y; BMI: 22.3±3.5 kg·m-2; caffeine intake: 204±89 mg·day-1; Mean±SD) who had normal sleeping patterns (≥8 h sleep/night) participated in this double-blind, placebo-controlled, randomised study. Following one night of normal sleep (Day 0: ≥8 h time in bed (TIB)), participants underwent three consecutive nights of restricted sleep (Day 1, 2, 3: 5 h TIB). Participants received caffeine (200 mg; n=10) or placebo (n=10) capsules, together with a decaffeinated coffee and standardised breakfast each morning. All participants received caffeine (100 mg) capsules to consume in the afternoon of each trial day. On Day 0, 1 and 3, participants completed visual analog scales to measure subjective ratings of alertness, concentration and tiredness, before and 1 h after capsule administration. Cognitive function was examined 1 h after capsule administration using a computerised Choice Reaction Time (CRT) task. Response speed and accuracy were the outcome variables. Analysis of response speed was conducted using both traditional central tendency measures (comparing mean and variance) and ex-Gaussian distributional analysis. Driving performance was assessed using a 30 min simulated driving task. Lateral (standard deviation of lane position [SDLP] and total number of line crossings [LC]) and longitudinal (standard deviation of speed [SDSP]) measures of vehicular control were the outcome variables. Results: Alertness and concentration significantly decreased, and tiredness increased across the three days of sleep restriction (all p's< 0.001). Caffeine only marginally alleviated these effects. No differences were observed between treatments or across trial days for response speed and accuracy on the CRT task, irrespective of the analytical approach employed. Likewise, no significant differences were observed between groups or across trial days for lateral (SDLP, LC) and longitudinal (SDSP) measures of simulated driving performance. Conclusion: Overall, results from this study indicate that three consecutive days of sleep restriction may influence subjective ratings of alertness, concentration and tiredness, but does not appear to impact CRT or simulated driving performance. Caffeine may alleviate some of the negative subjective effects imposed by restricted sleep, but the efficacy of caffeine to attenuate performance changes in cognitive function and driving performance were unable to be observed in this study.

One night of sleep deprivation impairs executive function but does not affect psychomotor or motor performance.

The current study assessed the impact of one night of sleep deprivation on cognitive, motor and psychomotor performance. Thirty healthy young adult male subjects completed a 24 h control or 24 h sleep deprived trial. For the control trial, participants (N = 15) were allowed normal night sleep (~8 h). For the sleep deprived trial, participants (N = 15) did not sleep for 24 h. Cognitive performance during go/no-go, Stroop and simple reaction tasks, psychomotor performance during speed-accuracy tasks with fixed and unfixed targets, and motor performance during countermovement jump, hand grip strength, and 30-s maximal voluntary contraction tasks were evaluated on day 1 at 8 am and 7 pm and on day 2 at 8 am. One night of sleep deprivation impaired psychological well-being and executive function but did not affect simple reaction time, the capacity for arm and leg muscle contraction, motor control performance during a speed–accuracy task with both fixed and unfixed targets, and central and peripheral motor fatigue in the 30 s maximal voluntary contraction task. The present study showed that one night of sleep deprivation resulted in executive function deterioration but did not modify motor control or maximal effort requiring performance of motor tasks.

Eye-Blink Parameters Detect On-Road Track-Driving Impairment Following Severe Sleep Deprivation.

Drowsiness leads to 20% of fatal road crashes, while inability to assess drowsiness has hampered drowsiness interventions. This study examined the accuracy of eye-blink parameters for detecting drowsiness related driving impairment in real time. Twelve participants undertook two sessions of 2-hour track-driving in an instrumented vehicle following a normal night's sleep or 32 to 34 hours of extended wake in a randomized crossover design. Eye-blink parameters and lane excursion events were monitored continuously. Sleep deprivation increased the rates of out-of-lane driving events and early drive terminations. Episodes of prolonged eyelid closures, blink duration, the ratio of amplitude to velocity of eyelid closure, and John's Drowsiness Score (JDS, a composite score) were also increased following sleep deprivation. A time-on-task (drive duration) effect was evident for out-of-lane events rate and most eye-blink parameters after sleep deprivation. The JDS demonstrated the strongest association with the odds of out-of-lane events in the same minute, whereas measures of blink duration and prolonged eye closure were stronger indicators of risk for out-of-lane events over longer periods of 5 minutes and 15 minutes, respectively. Eye-blink parameters also achieved moderate accuracies (specificities from 70.12% to 84.15% at a sensitivity of 50%) for detecting out-of-lane events in the same minute, with stronger associations over longer timeframes of 5 minutes to 15 minutes. Eyelid closure parameters are useful tools for monitoring and predicting drowsiness-related driving impairment (out-of-lane events) that could be utilized for monitoring drowsiness and assessing the efficacy of drowsiness interventions. This study is registered with the Australian New Zealand Clinical Trial Registry (ANCTR), http://www.anzctr.org.au/TrialSearch.aspx ACTRN12612000102875. Shekari Soleimanloo S, Wilkinson VE, Cori JM,Westlake J, Stevens B, Downey LA, Shiferaw BA, Rajaratnam SMW, Howard ME. Eye-blink parameters detect on-road track-driving impairment following severe sleep deprivation. J Clin Sleep Med. 2019;15(9):1271-1284.

Does splitting sleep improve long-term memory in chronically sleep deprived adolescents?

Sleep aids the encoding and consolidation of declarative memories, but many adolescents do not obtain the recommended amount of sleep each night. After a normal night of sleep, there is abundant evidence that a daytime nap enhances the consolidation of material learned before sleep and also improves the encoding of new information upon waking. However, it remains unclear how learning is affected when sleep is split between nocturnal and daytime nap periods during a typical school week of restricted sleep. We compared long-term memory in 58 adolescents who underwent two simulated school weeks of suboptimal continuous (6.5 h nocturnal sleep opportunity) or split sleep (5 h nocturnal sleep +1.5 h daytime nap at 14:00). In the first week, participants encoded pictures in the late afternoon on Day 5 and were tested after 2-nights of recovery sleep. On 3 consecutive days in the second week, participants learned about six species of amphibians in the morning, and six different amphibians in the late afternoon. Testing was performed in the evening following a night of recovery sleep. In the first week, the split sleep group recognized more pictures. In the second week, they remembered more facts about species learned in the afternoon. Groups did not differ for species learned in the morning. This suggests that under conditions of sleep restriction, a split sleep schedule benefits learning after a nap opportunity without impairing morning learning, despite less preceding nocturnal sleep. While not replacing adequate nocturnal sleep, a split sleep schedule may be beneficial for chronically sleep restricted learners.

Sleep influences cognitive performance in lemurs.

Primates spend almost half their lives asleep, yet little is known about how sleep influences their waking cognition. We hypothesized that diurnal and cathemeral lemurs differ in their need for consistent, non-segmented sleep for next-day cognitive function-including long-term memory consolidation, self-control, foraging efficiency, and sociality. Specifically, we expected that strictly diurnal Propithecus is more reliant on uninterrupted sleep for cognitive performance, as compared to four other lemur species that are more flexibly active (i.e., cathemeral). We experimentally inhibited sleep and tested next-day performance in 30 individuals of 5 lemur species over 960 total nights at the Duke Lemur Center in Durham, North Carolina. Each set of pair-housed lemurs experienced a sleep restriction and/or deprivation protocol and was subsequently tested in a variety of fitness-relevant cognitive tasks. Within-subject comparisons of performance on these tasks were made by switching the pair from the experimental sleep inhibited condition to a normal sleep environment, thus ensuring cognitive equivalency among individuals. We validated effectiveness of the protocol via actigraphy and infrared videography. Our results suggest that 'normal' non-disrupted sleep improved memory consolidation for all lemurs. Additionally, on nights of normal sleep, diurnal lemurs performed better in foraging efficiency tasks than cathemeral lemurs. Social behaviors changed in species-specific ways after exposure to experimental conditions, and self-control was not significantly linked with sleep condition. Based on these findings, the links between sleep, learning, and memory consolidation appear to be evolutionarily conserved in primates.

Can the Combination of Acute Alcohol Intake and One Night of Sleep Deprivation Affect Neuromuscular Performance in Healthy Male Adults? A Cross-over Randomized Controlled Trial.

Rodrigues, R, Franke, RA, Teixeira, BC, Macedo, RCO, Diefenthaeler, F, Baroni, BM, and Vaz, MA. Can the combination of acute alcohol intake and one night of sleep deprivation affect neuromuscular performance in healthy male adults? A cross-over randomized controlled trial. J Strength Cond Res 33(5): 1244-1251, 2019-The aim of this work was to perform a cross-over study to compare isolated and combined effects of alcohol intake and sleep deprivation on neuromuscular responses. Ten young and physically active male subjects were allocated to 4 conditions: (a) placebo intake + normal sleep (PLA + SLE); (b) alcohol intake + normal sleep (ALC + SLE); (c) placebo intake + sleep deprivation (PLA + SDP); and (d) alcohol intake + sleep deprivation (ALC + SDP). In each condition, volunteers ingested 1 g of alcohol per kg of body mass of alcoholic beer or nonalcoholic beer (placebo), followed by one night of normal sleep or sleep deprivation. In the next morning, neuromuscular performance (knee extensor isometric and concentric peak torque and time to task failure during the endurance test) and muscle activation were assessed. No differences were observed in the neuromuscular performance. We observed a significant reduction in quadriceps activation during the knee extensor isometric test in ALC + SDP compared with PLA + SLE (-20.8%; p = 0.02; d = 0.56). Our results demonstrated that acute alcohol intake and one night of sleep deprivation reduced quadriceps muscle activation without impact on neuromuscular performance.

The effect of sleep deprivation on objective and subjective measures of facial appearance.

The faces of people who are sleep deprived are perceived by others as looking paler, less healthy and less attractive compared to when well rested. However, there is little research using objective measures to investigate sleep-loss-related changes in facial appearance. We aimed to assess the effects of sleep deprivation on skin colour, eye openness, mouth curvature and periorbital darkness using objective measures, as well as to replicate previous findings for subjective ratings. We also investigated the extent to which these facial features predicted ratings of fatigue by others and could be used to classify the sleep condition of the person. Subjects (n=181) were randomised to one night of total sleep deprivation or a night of normal sleep (8-9hr in bed). The following day facial photographs were taken and, in a subset (n=141), skin colour was measured using spectrophotometry. A separate set of participants (n=63) later rated the photographs in terms of health, paleness and fatigue. The photographs were also digitally analysed with respect to eye openness, mouth curvature and periorbital darkness. The results showed that neither sleep deprivation nor the subjects' sleepiness was related to differences in any facial variable. Similarly, there was no difference in subjective ratings between the groups. Decreased skin yellowness, less eye openness, downward mouth curvature and periorbital darkness all predicted increased fatigue ratings by others. However, the combination of appearance variables could not be accurately used to classify sleep condition. These findings have implications for both face-to-face and computerised visual assessment of sleep loss and fatigue.

Sleep restriction caused impaired emotional regulation without detectable brain activation changes-a functional magnetic resonance imaging study.

Sleep restriction has been proposed to cause impaired emotional processing and emotional regulation by inhibiting top-down control from prefrontal cortex to amygdala. Intentional emotional regulation after sleep restriction has, however, never been studied using brain imaging. We aimed here to investigate the effect of partial sleep restriction on emotional regulation through cognitive reappraisal. Forty-seven young (age 20–30) and 33 older (age 65–75) participants (38/23 with complete data and successful sleep intervention) performed a cognitive reappraisal task during fMRI after a night of normal sleep and after restricted sleep (3 h). Emotional downregulation was associated with significantly increased activity in the dorsolateral prefrontal cortex (pFWE < 0.05) and lateral orbital cortex (pFWE < 0.05) in young, but not in older subjects. Sleep restriction was associated with a decrease in self-reported regulation success to negative stimuli (p < 0.01) and a trend towards perceiving all stimuli as less negative (p = 0.07) in young participants. No effects of sleep restriction on brain activity nor connectivity were found in either age group. In conclusion, our data do not support the idea of a prefrontal-amygdala disconnect after sleep restriction, and neural mechanisms underlying behavioural effects on emotional regulation after insufficient sleep require further investigation.

Оценка потенциальных возможностей амбулаторного устройства Dreem, предназначенного для ЭЭГ-синхронизированной акустической стимуляции во время сна

Sleep disorders are one of the significant problems in the modern society. Current research is on the lookout for the nonpharmacological ways to improve sleep quality and slow wave brain activity that plays a crucial role in homeostasis and cognitive functions. One of the promising approaches is acoustic stimulation that is phase-locked to deep sleep EEG rhythms. It was already shown that such stimulation improves slow wave brain activity. This article describes Dreem: a wireless consumer device that performs acoustic sleep stimulation in home conditions. The device has dry EEG electrodes, photo sensor for pulse oximetry, and an accelerometer. The inbuilt software detects deep sleep, performs audio stimulation on the ascending slope of the delta wave and does automatic sleep staging. In the pilot study of the device, three subjects made 10 to 24 recordings of night sleep with EEG recording and stimulation. The raw data recorded by the device is available to the user and is sufficient for sleep staging and basic sleep analysis. Automatic hypnograms reflect the structure of a normal night sleep. EEG averaged by the stimulation markers demonstrated the high efficacy of slow wave detectors and placement of stimulations on the ascending slope of a delta wave. Dreem device is of interest for the sleep researchers as an easy to use tool for an out-of-lab data acquisition.

Effects of Sleep Fragmentation and Induced Mood on Pain Tolerance and Pain Sensitivity in Young Healthy Adults.

Background: Experimental research exploring the sleep/pain-relationship has typically focused on total or partial sleep deprivation, hereby failing to reproduce the mere fragmented sleep pattern typically observed in patients with chronic pain. Further, little research is done on how affect moderates the sleep–pain relationship after sleep fragmentation. The present study sought to clarify the relationship between pain, sleep and positive and negative affect.Methods: In an experimental counterbalanced crossover design, 35 healthy young adults were subjected to several pain measures after one night of fragmented sleep, compared to one control night of normal sleep, both conducted in their own homes, and respectively, positive and negative affect induction using validated film clips and facial feedback procedures. Sleep was monitored using sleep diaries.Results: Increased pain sensitivity after one night of experimentally induced sleep fragmentation was found, compared to after one control night of undisturbed sleep. No main effects of induced affect on pain were found, and sleep x induced affect interaction was not significant.Conclusion: The present study supports the adverse effect of sleep fragmentation on pain sensitivity, however, affect was not found to be a moderator in the sleep–pain relationship. The results underline the need for further research within this field.

Combining trait and state model systems of psychosis: The effect of sleep deprivation on cognitive functions in schizotypal individuals

Model systems of psychosis play an important role in pathophysiology and drug development research. Schizotypal individuals display similar cognitive impairments as schizophrenia patients in several domains. Therefore, schizotypy may be interpreted as a trait model system of psychosis. In addition, experimentally controlled sleep deprivation is a putative state psychosis model that evokes subclinical psychosis-like states. We aimed to further validate these model systems by examining them in relation to central cognitive biomarkers of schizophrenia. Most of all, we were interested in investigating, for the first time, effects of their combination on cognitive function. Healthy subjects with high (N = 17) or low (N = 19) levels of schizotypy performed a cognitive task battery after one night of normal sleep and after 24 h of sleep deprivation. Sleep deprivation impaired performance in the go/nogo and n-back tasks relative to the normal sleep control condition. No differences between groups or interactions of group with sleep condition were found. The role of sleep deprivation as a model of psychosis is thus supported to some extent by impairments in inhibitory control. However, classical measures of cognition may be less able to detect deficits in schizotypy, in line with evidence of more basic information processing dysfunctions in schizotypy.

Sleep deprivation selectively enhances interpersonal emotion recognition from dynamic facial expressions at long viewing times: An observational study

Observational and experimental studies have shown that sleep deprivation disinhibits emotional responses to disturbing and rewarding external events. On the other hand, most studies on sleep deprivation and interpersonal emotion recognition report that sensitivity to others’ emotions is dampened during sleep deprivation. This is at odds with current neuroscientific theories of social cognition that assume that affective experiences and emotion recognition in others are closely tied at the neural and physiological level. In this observational study we show that sleep deprivation can actually increase emotion recognition accuracy from dynamically unfolding facial expressions if they are viewed sufficiently long. Participants viewed 2–4 s or 8–10s video clips of female senders who facially communicated anger, disgust, fear or sadness to their romantic partner and evaluated the sender’s affective state in a forced-choice paradigm, either during sleep deprivation after a night shift (N = 40) or after normal night sleep (N = 50). All participants showed a significant increase in emotion recognition accuracy from 2–4 s to 8–10 s stimulus presentation times. Emotion recognition accuracy did not differ between sleep-deprived and control participants for 2–4 s videos, but sleep-deprived participants showed significantly higher emotion recognition accuracy than control participants for 8–10 s videos. We surmise that this effect might be due to the break-down of prefrontal activity associated with sleep deprivation, which might not only disinhibit affective responses to external events but might also release simulation-based neural processes that contribute to interpersonal emotion recognition from dynamic facial expressions at longer time scales than usually investigated in emotion recognition studies.

Sleep deprivation affects post-lunch dip performances, biomarkers of muscle damage and antioxidant status.

To compare the effects of two types of partial sleep deprivation (PSD) at the beginning (PSDBN) and the end (PSDEN) of the night on mood, cognitive performances, biomarkers of muscle damage, haematological status and antioxidant responses before and after repeated-sprint exercise in the post-lunch dip. Fourteen male athletes performed the Running-based Anaerobic Sprint Test following: (i) baseline normal sleep night, (ii) PSDBN, or (iii) PSDEN in a randomized and counter-balanced order. During each condition, participants performed simple and choice reaction time tests, the Profile of Mood States, subjective sleepiness, and the Running-based Anaerobic Sprint Test. Plasma biomarkers of muscle damage, total blood count, and antioxidant activities were measured at rest and after the repeated sprint in the three conditions. PSDEN decreased Pmax (p=0.008; d=1.12), Pmean (p=0.002; d=1.33) and Pmin (p=0.006; d=1.15), whilst PSDBN decreased Pmean (p=0.04; d=0.68) and Pmin (p=0.028; d=0.58), in comparison with baseline. PSDEN exerted stronger effects on Pmax (p=0.013; d=0.74) and Pmean (p=0.048; d=0.54) than PSDBN. Moreover, PSDEN increased subjective sleepiness (p<0.001; d=1.93), while PSDBN impaired choice reaction time (p<0.001, d=1.89). Both PSD types decreased resting glutathione peroxidase (p<0.001; d=5.43, d=3.86), and increased aspartate amino-transferase levels (p<0.001; d=1.36, d=1.37) respectively for PSDEN and PSDBN. PSDEN decreased repeated-sprint performances more than PSDBN in the post-lunch dip. This could be explained by the lowered mood and resting antioxidant status and the increased inflammatory profile after PSDEN. Repeated-sprint exercise resulted in greater inflammation after PSDEN, despite the decreased physical performance. The drop of resting antioxidant defence and haemoglobin concentration after PSDEN could explain the increased sleep drive at the post-lunch dip.

How sleep loss leads to weight gain

Physiology Chronic sleep loss can have negative health effects, including weight gain and type 2 diabetes. Underlying molecular processes in key metabolic tissues are thought to be to blame. Cedernaes et al. compared molecular changes such as DNA methylation in fat and skeletal muscle tissue samples taken from 15 young Caucasian males after a night of sleep loss and after a normal night's sleep. The two tissue types responded very differently. In muscle, sleep loss enhanced skeletal muscle breakdown by down-regulating a metabolic pathway. However, the same pathway was up-regulated in fat tissue after disrupted sleep. Thus, sleep loss may reprogram fat tissue to increase fat storage. Sci. Adv. 10.1126/sciadv.aar8590 (2018).

Does sleep deprivation increase the vulnerability to acute psychosocial stress in young and older adults?

Sleep loss and psychosocial stress often co-occur in today’s society, but there is limited knowledge on the combined effects. Therefore, this experimental study investigated whether one night of sleep deprivation affects the response to a psychosocial challenge. A second aim was to examine if older adults, who may be less affected by both sleep deprivation and stress, react differently than young adults. 124 young (18–30 years) and 94 older (60–72 years) healthy adults participated in one of four conditions: i. normal night sleep & Placebo-Trier Social Stress Test (TSST), ii. normal night sleep & Trier Social Stress Test, iii. sleep deprivation & Placebo-TSST, iv. sleep deprivation & TSST. Subjective stress ratings, heart rate variability (HRV), salivary alpha amylase (sAA) and cortisol were measured throughout the protocol. At the baseline pre-stress measurement, salivary cortisol and subjective stress values were higher in sleep deprived than in rested participants. However, the reactivity to and recovery from the TSST was not significantly different after sleep deprivation for any of the outcome measures. Older adults showed higher subjective stress, higher sAA and lower HRV at baseline, indicating increased basal autonomic activity. Cortisol trajectories and HRV slightly differed in older adults compared with younger adults (regardless of the TSST). Moreover, age did not moderate the effect of sleep deprivation. Taken together, the results show increased stress levels after sleep deprivation, but do not confirm the assumption that one night of sleep deprivation increases the responsivity to an acute psychosocial challenge.

Total Sleep Deprivation and Recovery Sleep Affect the Diurnal Variation of Agility Performance: The Gender Differences.

Romdhani, M, Hammouda, O, Smari, K, Chaabouni, Y, Mahdouani, K, Driss, T, and Souissi, N. Total sleep deprivation and recovery sleep affect the diurnal variation of agility performance: The gender differences. J Strength Cond Res 35(1): 132-140, 2021-This study aimed to investigate the effects of time-of-day, 24 and 36 hours of total sleep deprivation (TSD), and recovery sleep (RS) on repeated-agility performances. Twenty-two physical education students (11 male and 11 female students) completed 5 repeated modified agility T-test (RMAT) sessions (i.e., 2 after normal sleep night [NSN] [at 07:00 and 17:00 hours], 2 after TSD [at 07:00 hours, i.e., 24-hour TSD and at 17:00 hours, i.e., 36-hour TSD], and 1 after RS at 17:00 hours). The RMAT index decreased from the morning to the afternoon after NSN (p < 0.05, d = 1.05; p < 0.01, d = 0.73) and after TSD (p < 0.001, d = 0.92; d = 1.08), respectively, for total time (TT) and peak time (PT). This finding indicates a diurnal variation in repeated agility, which persisted after TSD. However, the diurnal increase in PT was less marked in the female group after NSN (2.98 vs. 6.24%). Moreover, TT and PT increased, respectively, after 24-hour TSD (p < 0.001; d = 0.84, d = 0.87) and 36-hour TSD (p < 0.001, d = 1.12; p < 0.01, d = 0.65). Female subjects' PT was less affected by 24-hour TSD (1.76 vs. 6.81%) compared with male subjects' PT. After 36-hour TSD, the amount of decrease was not different between groups, which increased the diurnal amplitude of PT only for male subjects. Total sleep deprivation suppressed the diurnal increase of PT and increased the diurnal amplitude of oral temperature only in women. Nevertheless, RS normalized the sleep-loss-induced performance disruption. Conclusively, sleep loss and RS differently affect repeated-agility performance of men and women during the day. Sleep extension postdeprivation could have potent restorative effect on repeated-agility performances, and female subjects could extract greater benefits.

Effects of a 20-Min Nap Post Normal and Jet Lag Conditions on P300 Components in Athletes.

Post-lunch sleepiness belongs to biological rhythms. Athletes take a nap to counteract afternoon circadian nadir, in prevision of disturbed sleep. This study examined the effects of brief post-lunch nap on vigilance in young and healthy athletes. The P300 components, physiological and cognitive performances were assessed either after nap or rest, following a night of normal sleep (NSC) or simulated jet lag condition (5-h advance-JLC). P300 wave is the positive deflection at about 300 ms in response to a rare stimulus, representing higher information processing. P300 amplitude reflects the amount of attention allocated whereas P300 latency reflects time spent on stimulus classification. P300 amplitude was significantly increased (Fz:11.14±3.0vs9.05±3.2 µV; p<0.05) and P300 latency was shorter (Pz:327.16±18.0vs344.90±17.0 ms; p<0.01) after nap in NSC. These changes were accompanied by lower subjective sleepiness (19.7±9.6vs27.5±16.5; p<0.05) and decrease in mean reaction times (MRT: divided attention, 645.1±74.2vs698±80.4 ms; p<0.05). In contrast, in JLC, only P300 amplitudes (Fz:10.30±3.1vs7.54±3.3 µV; p<0.01 and Cz: 11.48±3.1vs9.77±3.6 µV; p<0.05) increased but P300 latencies or MRT did not improve. These results indicated improvements in speed of stimulus evaluation time. Napping positively impacts on cognitive processing, especially when subjects are on normal sleep schedules. A nap should be planned for athletes whose performance requires speedy and accurate decisions.