The effect of overnight sleep deprivation after competitive rugby league matches on postmatch physiological and perceptual recovery

PURPOSE: This study examined the effects of overnight sleep deprivation on recovery following competitive rugby league matches. METHODS: Eleven male, amateur rugby league players performed two competitive matches, followed by either a normal night's sleep (~8h; CONT) or a sleep deprived night (~0h; SDEP) in a randomised fashion. Testing was conducted the morning of the match, and immediately post-match, 2h post and the next morning (16h post-match). Measures included counter-movement jump (CMJ) distance, knee extensor maximal voluntary contraction (MVC), voluntary activation (VA), venous blood creatine kinase (CK) and C-reactive protein (CRP), perceived muscle soreness and a word-colour recognition cognitive function test. Percent change between post- and 16h post-match was reported to determine the effect of the intervention the next morning. RESULTS: Large effects indicated a greater post- to 16h post-match percentage decline in CMJ distance following SDEP compared to CONT (P=0.10-0.16; d=0.95-1.05). Similarly, the percentage decline in incongruent word-colour reaction times were increased in SDEP trials (P=0.007; d=1.75). Measures of MVC did not differ between conditions (P=0.40-0.75; d=0.13-0.33), though trends for larger percentage decline in VA were detected in SDEP (P=0.19; d=0.84). Further, large effects indicated higher CK and CRP responses 16h post-match during SDEP compared to CONT (P=0.11-0.87; d=0.80-0.88). CONCLUSIONS: Sleep deprivation negatively affected recovery following a rugby league match, specifically impairing CMJ distance and cognitive function. Practitioners should promote adequate post-match sleep patterns or adjust training demands the next day to accommodate the altered physical and cognitive state following sleep deprivation.

The effects of sleep restriction on executive inhibitory control and affect in young adults

Purpose: Young adults regularly experience restricted sleep due to a range of social, educational and vocational commitments. Evidence suggests that extended periods of sleep deprivation negatively impact affective and inhibitory control mechanisms leading to behavioural consequences such as increased emotional reactivity and impulsive behaviour. It is less clear whether acute periods of restricted sleep produce the same behavioural consequences. Methods: Nineteen young adults (m = 8, f = 12) with habitual late bed-time (after 22:30 h) and wake-time (after 06:30 h) completed a range of objective and subjective measures assessing sleepiness (Psychomotor Vigilance Task, Karolinska Sleepiness Scale), inhibitory control (Emotional Go/No-go Task and a Balloon Analog Risk Task) and affect (Positive and Negative Affective Schedule). Testing was counterbalanced across participants, and occurred on two occasions once following restricted sleep and once following habitual sleep one week apart. Results: Compared to habitual sleep, sleep restriction produced significantly slower performance on the Psychomotor Vigilance Task, and higher subjective ratings of sleepiness on the Karolinska Sleepiness Scale. Sleep restriction also caused a significant decrease in positive affect, but no change in negative affect on the Affective Schedule. Inhibitory control efficiency was significantly differentiated, with participants showing an increase in risk taking on the Balloon Analog Risk Task, but there was no evidence of increased reactivity to negative stimuli on the Emotional Go/No-go task. Conclusions: Results suggest that even acute periods of sleep loss may cause deficits in affective experiences and increase impulsive and potentially high risk behaviour in young adults.

The effect of sleep deprivation on BOLD activity elicited by a divided attention task

Sleep loss, widespread in today’s society and associated with a number of clinical conditions, has a detrimental effect on a variety of cognitive domains including attention. This study examined the sequelae of sleep deprivation upon BOLD fMRI activation during divided attention. Twelve healthy males completed two randomized sessions; one after 27 h of sleep deprivation and one after a normal night of sleep. During each session, BOLD fMRI was measured while subjects completed a cross-modal divided attention task (visual and auditory). After normal sleep, increased BOLD activation was observed bilaterally in the superior frontal gyrus and the inferior parietal lobe during divided attention performance. Subjects reported feeling significantly more sleepy in the sleep deprivation session, and there was a trend towards poorer divided attention task performance. Sleep deprivation led to a down regulation of activation in the left superior frontal gyrus, possibly reflecting an attenuation of top-down control mechanisms on the attentional system. These findings have implications for understanding the neural correlates of divided attention and the neurofunctional changes that occur in individuals who are sleep deprived.

The effect of light on cognitive performance of partially sleep-deprived young drivers

Sleepiness remains a primary cause of road crashes, the major cause of death in young adults. Light is known to produce a direct alerting effect, but little is known about its effects on sleepy drivers. This study aimed to compare the effect of blue-green light and caffeine on young drivers’ cognitive performance after chronic-partial sleep loss.

Driver sleepiness—Comparisons between young and older men during a monotonous afternoon simulated drive

Young men figure prominently in sleep-related road crashes. Non-driving studies show them to be particularly vulnerable to sleep loss, compared with older men. We assessed the effect of a normal night's sleep vs. prior sleep restricted to 5 h, in a counterbalanced design, on prolonged (2 h) afternoon simulated driving in 20 younger (av. 23 y) and 19 older (av. 67 y) healthy men. Driving was monitored for sleepiness related lane deviations, EEGs were recorded continuously and subjective ratings of sleepiness taken every 200 s. Following normal sleep there were no differences between groups for any measure. After sleep restriction younger drivers showed significantly more sleepiness-related deviations and greater 4–11 Hz EEG power, indicative of sleepiness. There was a near significant increase in subjective sleepiness. Correlations between the EEG and subjective measures were highly significant for both groups, indicating good self-insight into increasing sleepiness. We confirm the greater vulnerability of younger drivers to sleep loss under prolonged afternoon driving.

Insomnia : A Self Help Handbook

This book is a practical and useful tool for getting your sleep back on track. Even if you have suffered from insomnia for many years, this book contains simple, easy to learn strategies to manage your sleep loss through evidence-based techniques such as cognitive therapy and stimulus control. Dr. Sacre will guide you through these approaches and explain how they work and why they are recommended above other approaches. There is a chapter on special populations that tells you what to do if you are a shift worker, long distance traveller, parent, older adult, woman (including pregnancy and menopause) or an elite athlete. If you want to enjoy natural, healthy and satisfying sleep again, this handbook gives you all the tools you need to achieve it. You only need to have the motivation and discipline to apply the strategies and stick to them over time. This handbook first explains what normal sleep is all about and challenges some myths about sleep and insomnia. Then you will be guided through a thorough sleep assessment. Insomnia is then described in detail including different types of insomnia and the kinds of factors that contribute to sleep loss. Through the following chapters, you will be shown step-by-step what to do to bring about change in your sleeping patterns and habits, through addressing the factors that perpetuate poor sleep. These factors mainly revolve around unhelpful thinking, compensatory behaviors, poor sleep hygiene and environmental influences. These are all things that are within your control and Dr. Sacre will show you how. Dr. Sacre has worked in the fields of sleep health, mental health and addictive disorders for 25 years and over that time, she has encountered hundreds of people who have struggled with insomnia and sleep loss due to other causes. She currently heads the Therapy Programs department at Belmont Private Hospital in Brisbane, Australia, where there is an emphasis on Cognitive Behavioral Therapy, including a Cognitive Behavioral Therapy for Insomnia (CBT-i) program. A psychologist and nurse, Dr. Sacre is a long-time member of the Australasian Sleep Association and the Australian Psychological Society. She has conducted research into the function of dreaming, online sleep surveys and the usefulness of sleep self-help guides for students, older adults and carers of people with dementia. She has also published on diverse topics, including the management of nightmares in war veterans. She is an Adjunct Associate Professor at Queensland University of Technology, Brisbane and lectures professionals, including psychologists, school counselors and psychiatrists, on sleep disorders and their management as well as Cognitive Behavioral Therapy.

Enhanced preference for high-fat foods following a simulated night shift

Objectives Shift workers are prone to obesity and associated co-morbidities such as diabetes and cardiovascular disease. Sleep restriction associated with shift work results in dramatic endocrine and metabolic effects that predispose shift workers to these adverse health consequences. While sleep restriction has been associated with increased caloric intake, food preference may also play a key role in weight gain associated with shift work. This study examined the impact of an overnight simulated night shift on food preference. Methods Sixteen participants [mean 20.1, standard deviation (SD) 1.4 years; 8 women] underwent a simulated night shift and control condition in a counterbalanced order. On the following morning, participants were provided an opportunity for breakfast that included high- and low-fat food options (mean 64.8% and 6.4% fat, respectively). Results Participants ate significantly more high-fat breakfast items after the simulated night shift than after the control condition [167.3, standard error of the mean (SEM 28.7) g versus 211.4 (SEM 35.6) g; P=0.012]. The preference for high-fat food was apparent among the majority of individuals following the simulated night shift (81%), but not for the control condition (31%). Shift work and control conditions did not differ, however, in the total amount of food or calories consumed. Conclusions A simulated night shift leads to preference for high-fat food during a subsequent breakfast opportunity. These results suggest that food choice may contribute to weight-related chronic health problems commonly seen among night shift workers.

Liking for high fat foods in patients with Obstructive Sleep Apnoea

Excess weight and obesity are factors that are strongly associated with risk for Obstructive Sleep Apnoea (OSA).Weight loss has been associated with improvements in clinical indicators of OSA severity; however, patients’ beliefs about diet change have not been investigated. This study utilized a validated behaviour change model to estimate the relationship between food liking, food intake and indices of OSA severity. Two-hundred and six OSA patients recruited from a Sleep Disorders Clinic completed standardized questionnaires of: a) fat and fibre food intake, food liking, and food knowledge and; b) attitudes and intentions towards fat reduction. OSA severity and body mass index (BMI) were objectively measured using standard clinical guidelines. The relationship between liking for high fat food and OSA severity was tested with hierarchical regression. Gender and BMI explained a significant 20% of the variance in OSA severity, Fibre Liking accounted for an additional 6% (a negative relationship), and Fat Liking accounted for a further 3.6% of variance. Although the majority of individuals (47%) were currently “active” in reducing fat intake, overall the patients’ dietary beliefs and behaviours did not correspond. The independent relationship between OSA severity and liking for high fat foods (and disliking of high fibre foods) may be consistent with a two-way interaction between sleep disruption and food choice. Whilst the majority of OSA patients were intentionally active in changing to a healthy diet, further emphasis on improving healthy eating practices and beliefs in this population is necessary.

Does psychological stress mediate social deprivation in tooth loss?

It is unclear which theoretical dimension of psychological stress affects health status. We hypothesized that both distress and coping mediate the relationship between socio-economic position and tooth loss. Cross-sectional data from 2915 middle-aged adults evaluated retention of < 20 teeth, behaviors, psychological stress, and sociodemographic characteristics. Principal components analysis of the Perceived Stress Scale (PSS) extracted 'distress' (a = 0.85) and 'coping' (a =0.83) factors, consistent with theory. Hierarchical entry of explanatory variables into age- and sex-adjusted logistic regression models estimated odds ratios (OR) and 95% confidence intervals [95% CI] for retention of < 20 teeth. Analysis of the separate contributions of distress and coping revealed a significant main effect of coping (OR = 0.7 [95% CI = 0.7-0.8]), but no effect for distress (OR = 1.0 [95% CI = 0.9-1.1]) or for the interaction of coping and distress. Behavior and psychological stress only modestly attenuated socio-economic inequality in retention of < 20 teeth, providing evidence to support a mediating role of coping.

Beyond Bryan: Builders' liability and pure economic loss

In Bryan v Maloney, the High Court extended a builder’s duty of care to encompass a liability in negligence for the pure economic loss sustained by a subsequent purchaser of a residential dwelling as a result of latent defects in the building’s construction. Recently, in Woolcock Street Investments Pty Ltd v CDG Pty Ltd, the Court refused to extend this liability to defects in commercial premises. The decision therefore provides an opportunity to re-examine the rationale and policy behind current jurisprudence governing builders’ liability for pure economic loss. In doing so, this article considers the principles relevant to the determination of a duty of care generally and whether the differences between purchasers of residential and commercial properties are as great as the case law suggests

Cues to starting CPAP in obstructive sleep apnoea : development and validation of the cues to CPAP Use Questionnaire (CCUQ)

Background: The reasons that a patient has to start treatment, their “Cues to Action”, are important for determining subsequent health behaviours. Cues to action are an explicit component of the Health Belief Model of CPAP acceptance adherence. At present there is no scale available to measure this construct for individuals with Obstructive Sleep Apnoea (OSA). This paper aims to develop, validate and describe responding patterns within an OSA patient sample to the Cues to CPAP Use Questionnaire (CCUQ).----- Method: Participants were 63 adult patients diagnosed with OSA who had never tried CPAP when initially recruited. The CCUQ was completed at one month after being prescribed CPAP.----- Results: Exploratory factor analysis (EFA) showed a three factor structure of the 9-item CCUQ, with “Health Cues”, “Partner Cues” and “Health Professional Cues” subscales accounting for 59.91% of the total variance. The CCUQ demonstrated modest internal consistency and split-half reliability. The questionnaire is brief and user-friendly, with readability at a 7th grade level. The most frequently endorsed cues for starting CPAP were Health Professional Cues (prompting by the sleep physician) and Health Cues such as tiredness and concern about health outcomes.----- Conclusions: This study validates a measure of an important motivational component of the Health Belief Model. Health Professional Cues and internal Health Cues were reported to be the most important prompts to commence CPAP by this patient sample.

Optimal allocation and sizing of capacitors to minimize the transmission line loss and to improve the voltage profile

To allocate and size capacitors in a distribution system, an optimization algorithm, called Discrete Particle Swarm Optimization (DPSO), is employed in this paper. The objective is to minimize the transmission line loss cost plus capacitors cost. During the optimization procedure, the bus voltage, the feeder current and the reactive power flowing back to the source side should be maintained within standard levels. To validate the proposed method, the semi-urban distribution system that is connected to bus 2 of the Roy Billinton Test System (RBTS) is used. This 37-bus distribution system has 22 loads being located in the secondary side of a distribution substation (33/11 kV). Reducing the transmission line loss in a standard system, in which the transmission line loss consists of only about 6.6 percent of total power, the capabilities of the proposed technique are seen to be validated.