Sleep deprivation, which is a decrease in duration and quality of sleep, is a common problem in today’s life. Epidemiological and interventional investigations have suggested a link between sleep deprivation and overweight/obesity. Sleep deprivation affects homeostatic and non-homoeostatic regulation of appetite, with the food reward system playing a dominant role. Factors such as sex and weight status affect this regulation; men and individuals with excess weight seem to be more sensitive to reward-driven and hedonistic regulation of food intake. Sleep deprivation may also affect weight through affecting physical activity and energy expenditure. In addition, sleep deprivation influences food selection and eating behaviours, which are mainly managed by the food reward system. Sleep-deprived individuals mostly crave for palatable energy-dense foods and have low desire for fruit and vegetables. Consumption of meals may not change but energy intake from snacks increases. The individuals have more desire for snacks with high sugar and saturated fat content. The relationship between sleep and the diet is mutual, implying that diet and eating behaviours also affect sleep duration and quality. Consuming healthy diets containing fruit and vegetables and food sources of protein and unsaturated fats and low quantities of saturated fat and sugar may be used as a diet strategy to improve sleep. Since the effects of sleep deficiency differ between animals and humans, only evidence from human subject studies has been included, controversies are discussed and the need for future investigations is highlighted.

The challenge of identifying efficacious out-patient treatments for depression is amplified by the increasing desire to find interventions that reduce the time to sustained improvement. One potential but underexplored option is triple chronotherapy (TCT). To date, use of TCT has been largely restricted to specialist units or in-patients. Recent research demonstrates that it may be possible to undertake sleep deprivation in out-patient settings, raising the possibility of delivering TCT to broader populations of individuals with depression. Emerging evidence suggests that out-patient TCT is a high-benefit, low-risk intervention but questions remain about how to target TCT and its mechanisms of action. Like traditional antidepressants, TCT probably acts through several pathways, especially the synchronisation of the ‘master clock’. Availability of reliable and valid methods of out-patient measurement of intra-individual circadian rhythmicity and light exposure are rate-limiting steps in the wider dissemination of TCT.

Energy deficit is common during prolonged periods of strenuous physical activity and limited sleep, but the extent to which appetite suppression contributes is unclear. The aim of this randomised crossover study was to determine the effects of energy balance on appetite and physiological mediators of appetite during a 72-h period of high physical activity energy expenditure (about 9·6 MJ/d (2300 kcal/d)) and limited sleep designed to simulate military operations (SUSOPS). Ten men consumed an energy-balanced diet while sedentary for 1 d (REST) followed by energy-balanced (BAL) and energy-deficient (DEF) controlled diets during SUSOPS. Appetite ratings, gastric emptying time (GET) and appetite-mediating hormone concentrations were measured. Energy balance was positive during BAL (18 (sd 20) %) and negative during DEF (–43 (sd 9) %). Relative to REST, hunger, desire to eat and prospective consumption ratings were all higher during DEF (26 (sd 40) %, 56 (sd 71) %, 28 (sd 34) %, respectively) and lower during BAL (–55 (sd 25) %, −52 (sd 27) %, −54 (sd 21) %, respectively; P condition < 0·05). Fullness ratings did not differ from REST during DEF, but were 65 (sd 61) % higher during BAL (P condition < 0·05). Regression analyses predicted hunger and prospective consumption would be reduced and fullness increased if energy balance was maintained during SUSOPS, and energy deficits of ≥25 % would be required to elicit increases in appetite. Between-condition differences in GET and appetite-mediating hormones identified slowed gastric emptying, increased anorexigenic hormone concentrations and decreased fasting acylated ghrelin concentrations as potential mechanisms of appetite suppression. Findings suggest that physiological responses that suppress appetite may deter energy balance from being achieved during prolonged periods of strenuous activity and limited sleep.

The lack of sleep is a significant problem in the modern world. The structure of the economy means that 24 hour working is required from some of us, sometimes because we are expected to be able to respond to share-price fluctuations on the other side of the planet, sometimes because we are expected to serve kebabs to people leaving nightclubs, and sometimes because lives depend on it. The immediate effect is that we feel groggy; but there may be much more sinister long-term effects of persistent sleep deprivation and disruption, the evidence for which is significant, and worth taking seriously. If sleeplessness has a serious impact on health, it represents a notable public health problem. In this article, I sketch that problem, and look at how exploiting the pharmacopoeia (or a possible future pharmacopoeia) might allow us to tackle it. I also suggest that using drugs to mitigate or militate against sleeplessness is potentially morally and politically fraught, with implications for social justice. Hence, whatever reasons we have to use drugs to deal with the problems of sleeplessness, we ought to be careful.

Introduction: Sleep deprivation negatively affects cognitive and behavioural performance. Emergency Medicine (EM) residents commonly work night shifts and are then expected to perform with competence. This study examines the impact of night shifts on EM resident performance in simulated resuscitation scenarios. Methods: A retrospective cohort study was completed at a single Canadian academic centre where residents participate in twice-annual simulation-based resuscitation objective structured clinical examinations (OSCEs). OSCE scores for all EM residents between 2010-2016 were collected, as well as post-graduate year (PGY1-5), gender, and shift schedules. OSCEs were scored using the Queen’s Simulation Assessment Tool (QSAT) evaluating four domains: primary assessment, diagnostic actions, therapeutic actions and communication, and an overall global assessment score (GAS). A night shift was defined as a late evening (beyond 23:00) or overnight shift within the three days before an OSCE. A mixed effects linear regression model was used to model the association between night shifts and OSCE scores while adjusting for gender and PGY. Results: A total of 136 OSCE scores were collected from 56 residents. PGY-5 residents had 37.1% (31.3 to 34.0%; p<0.01) higher OSCE scores than those in PGY-1 with an average increase of 8.8% (7.5 to 10.1%; p<0.01) per year. Working one or more night shifts in the three days before an OSCE reduced the total and communication scores by an average of 3.8% (p=0.04) and 4.5% (p=0.04) respectively. We observed a significant gender difference in the effects of acute shift work (p=0.03). Working a night shift one night prior to an OSCE was not associated with total score among male residents (p=0.33) but was associated with a 6.1% (-11.9 to -0.2; p=0.04) decrease in total score among female residents. This difference was consistent across PGY and was primarily due to an 8.5% (-15.5 to -1.6%; p=0.02) decrease in communication scores and a 6.7% (-13.1 to -0.3%; p=0.04) reduction in GAS. Conclusion: Proximity to night shifts significantly impaired the performance of EM trainees in simulated resuscitation scenarios, particularly in the domain of communication. For female residents, the magnitude of difference in total scores after working such shifts one night prior to a resuscitation OSCE was approximately equal to the difference seen between residents one year apart in training.

Unequivocal results demonstrating a causal relationship between a disturbance in circadian rhythms and depression have not yet been reported (reviews). However, acute mood changes, such as the antidepressive effect of sleep deprivation, diurnal variations of mood and their interrelationship, are commonly put forward as evidence of the importance of circadian dysregulations in affective disorders. The purpose of the present study is to obtain more insight in the mechanisms underlying these mood changes. The results will be discussed in the context of a recently postulated non-chronobiological explanation.

Earlier studies have suggested that the relationship between diurnal variation of mood and the response to total sleep deprivation (TSD) is clear and unambiguous: improvement of mood during the day prior to TSD (a positive diurnal variation) is followed by a positive response (mood improvement) to TSD, while no improvement or deterioration of mood during the day prior to TSD (a negative diurnal variation) may result in no, or even a negative, TSD response (for references see Van den Hoofdakker). However, these conclusions were based on the results from cross-sectional studies, comparing single TSD effects across individuals. Comparison of sleep deprivation effects within individuals, however, revealed that the course of mood during the day prior to TSD is irrelevant for the TSD response. Accordingly, a favourable response to TSD appeared to be related to the patient's propensity to show diurnal mood variations per se, irrespective of their direction.

In 1975 van den Burg and van den Hoofdakker hypothesized that depressed patients might be ‘overaroused.’ This suggestion is consistent not only with their seminal observations on the antidepressant effects of total sleep deprivation in depression, but with the short, fragmented, and shallow sleep of depressed patients, lowered arousal thresholds, hyperactivity of the hypothalamus-pituitary adrenal (HPA) axis, and elevated core body temperature commonly found in some patients during the sleep period.

Based on previous studies demonstrating detrimental effects of reduced alertness on attentional orienting our study seeks to examine covert and overt attentional orienting in different arousal states. We hypothesized an attentional asymmetry with increasing reaction times to stimuli presented to the left visual field in a state of maximally reduced arousal. Eleven healthy participants underwent sleep deprivation and were examined repeatedly every 4 hr over 28 hr in total with two tasks measuring covert and overt orienting of attention. Contrary to our hypothesis, a reduction of arousal did not induce any asymmetry of overt orienting. Even in participants with profound and significant attentional asymmetries in covert orienting no substantial reaction time differences between left- and right-sided targets in the overt orienting task could be observed. This result is not in agreement with assumptions of a tight coupling of covert and overt attentional processes. In conclusion, we found differential effects of lowered arousal induced by sleep deprivation on covert and overt orienting of attention. This pattern of results points to a neuronal non-overlap of brain structures subserving these functions and a differential influence of the norepinephrine system on these modes of spatial attention. (JINS, 2015, 21, 545–557)

The present study aimed to assess the adequacy of energy, macronutrients and water intakes of ultra-endurance runners (UER) competing in a 24 h ultra-marathon (distance range: 122–208 km). The ad libitum food and fluid intakes of the UER (n 25) were recorded throughout the competition and analysed using dietary analysis software. Body mass (BM), urinary ketone presence, plasma osmolality (POsmol) and volume change were determined at pre- and post-competition time points. Data were analysed using appropriate t tests, with significance set at P <0·05. The total energy intake and expenditure of the UER were 20 (sd 12) and 55 (sd 11) MJ, respectively (control (CON) (n 17): 12 (sd 1) and 14 (sd 5) MJ, respectively). The protein, carbohydrate and fat intakes of the UER were 1·1 (sd 0·4), 11·3 (sd 7·0) and 1·5 (sd 0·7) g/kg BM, respectively. The rate of carbohydrate intake during the competition was 37 (sd 24) g/h. The total water intake of the UER was 9·1 (sd 4·0) litres (CON: 2·1 (sd 1·0) litres), while the rate of water intake was 378 (sd 164) ml/h. Significant BM loss occurred at pre- to post-competition time points (P =0·001) in the UER (1·6 (sd 2·0) %). No significant changes in POsmol values were observed at pre- (285 (sd 11) mOsmol/kg) to post-competition (287 (sd 10) mOsmol/kg) time points in the UER and were lower than those recorded in the CON group (P <0·05). However, plasma volume (PV) increased at post-competition time points in the UER (10·2 (sd 9·7) %; P <0·001). Urinary ketones were evident in the post-competition samples of 90 % of the UER. Energy deficit was observed in all the UER, with only one UER achieving the benchmark recommendations for carbohydrate intake during endurance exercise. Despite the relatively low water intake rates recorded in the UER, hypohydration does not appear to be an issue, considering increases in PV values observed in the majority (80 %) of the UER. Population-specific dietary recommendations may be beneficial and warranted.