Sleep is vital for the maintenance of physical and mental health, recovery and performance in athletes. Sleep also has a restorative effect on the immune system and the endocrine system. Sleep must be of adequate duration, timing, and quality to promote recovery following training and competition. Inadequate sleep adversely impacts carbohydrate metabolism, appetite, energy intake and protein synthesis affecting recovery from the energy demands of daily living and training/competition related fatigue. Sleep’s role in overall health and wellbeing has been established. Athletes have high sleep needs and are particularly vulnerable to sleep difficulties due to high training and competition demands, as such the implementation of the potential nutritional interventions to improve sleep duration and quality is commonplace. The use of certain nutrition strategies and supplements has an evidence base i.e. carbohydrate, caffeine, creatine, kiwifruit, magnesium, meal make-up and timing, protein and tart cherry. However, further research involving both foods and supplements is necessary to clarify the interactions between nutrition and the circadian system as there is potential to improve sleep and recovery. Additional research is necessary to clarify guidelines and develop products and protocols for foods and supplements to benefit athlete health, performance and/or recovery. The purpose of this review is to highlight the potential interaction between sleep and nutrition for athletes, and how these interactions might benefit sleep and/or recovery.

Infant sleep quality is increasingly regarded as an important factor for children long-term functioning and adaptation. The early roots of sleep disturbances are still poorly understood and likely involve a complex interplay between prenatal and postnatal factors. This study investigated whether exclusive breastfeeding during the first 6 months moderated the association between maternal prenatal pandemic-related stress (PRS) and sleep problems in 24-months children born during the COVID-19 pandemic. We also explored the potential contribution of maternal postnatal anxiety in these relations. Seventy-eight infants (50% males) and their mothers provided complete data from birth to 24 months. Between 12 and 48 h from birth, maternal PRS during pregnancy was retrospectively reported as well as maternal anxiety and exclusive breastfeeding. Maternal anxiety and exclusive breastfeeding were also reported at 3 and 6 months after childbirth. Children sleep disturbances were reported at 24 months. Bayesian analyses revealed that maternal PRS was positively associated with sleep problems in children who were not exclusively breastfed from birth to 6 months. Findings add to the growing literature on the lasting impact of early pre- and postnatal experiences on child well-being and development.

This editorial summarises the clinical relevance of ‘chronopsychiatry’, defined as the interface between circadian science and mental health science. Chronopsychiatry represents a move towards time-variable perspectives on neurobiology and symptoms, with a greater emphasis on chronotherapeutic interventions.

I would like to thank Professor Ekirch for his reflections on ‘Have we lost sleep?’, which contain several points that I have already responded to within the paper following his peer review of my original submission to Medical History in 2023 (Professor Ekirch having voluntarily identified himself as a reviewer in a normally double-blind process). I acknowledge that the focus of my paper was on Ekirch’s original work from 2001; if I did not engage as he would have wished with his subsequent publications, this was simply because I do not perceive the same substantial developments in his thinking and research on the subject that he does. Indeed, the present critique by Ekirch amounts essentially to more of the same: a long list of references and quotes but little detailed discussion of any individual source. As my paper demonstrates, seemingly unambiguous evidence from a brief quotation can become less clear-cut when placed in context. I am sorry if I deploy the word ‘might’ more than Ekirch would like. This reflects, I hope, a healthy degree of uncertainty and intellectual humility in my approach to the complex issue of pre-industrial sleep. To extend Ekirch’s metaphor, if the jigsaw puzzle that both he and I are trying to assemble can take the form of a cat or a dog, it is possible that its true form is neither animal. The extent to which people woke in the night in pre-industrial Europe, the duration of such awakening, and the predominant cultural attitude towards this—concern, acceptance, or indifference—are topics about which it would seem wise to avoid sweeping statements and generalisations, given the relatively long period covered and the social, cultural, and individual diversity that must be taken into consideration. I can only repeat that I think amassing more brief references, and selectively citing relatively small physiological studies and anthropological evidence from global settings, is unlikely to provide much clarity, let alone definitive answers. I welcome Professor Ekirch’s contribution to this discussion as an indication that the question of segmented sleep in early modern Europe is by no means settled but is a matter of ongoing debate.

The objective was to examine associations between social jetlag and diet quality among young adults in the US using nationally representative data from the 2017–2018 NHANES survey, and evaluate effect modification by gender and race/ethnicity. Social jetlag was considered ≥2-hour difference in sleep midpoint (median of bedtime and wake time) between weekends and weekdays. Diet quality was assessed with the Healthy Eating Index (HEI)-2015 and its 13 dietary components. Ordinal logistic models were run with diet scores binned into tertiles as the outcome. Models accounted for potential confounders and survey weights. Effect modification by gender and race/ethnicity was examined. The study sample included 1,356 adults aged 20–39 years. 31% of young adults had social jetlag. Overall, there were no associations between social jetlag and diet quality. However, interaction analysis revealed several associations were race-specific (P, interaction<0.05). Among Black adults, social jetlag was associated with lower overall diet quality (OR = 0.4, 95% CI 0.2, 0.8; i.e. less likely to be in higher diet quality tertiles) and more unfavourable scores on Total Vegetables (OR = 0.6, 95% CI 0.3, 1.0) and Added Sugar (i.e. OR = 0.6, 95% CI 0.4, 0.9). For Hispanic adults, social jetlag was associated with worse scores for Sodium (OR = 0.6, 95% CI 0.4, 0.9) However, White adults with social jetlag had better scores of Greens and Beans (OR = 1.9, 95% CI 1.1, 3.2). Within a nationally representative sample of US young adults, social jetlag was related to certain indicators of lower diet quality among Black and Hispanic Americans.

The association of post-adoption experiences of discrimination with depressive symptoms was examined in 93 previously institutionalized (PI) youth (84% transracially adopted). Additionally, we explored whether sleep quality statistically moderated this association. Notably, we examined these associations after covarying a measure of autonomic balance (high/low frequency ratio in heart rate variability) affected by early institutional deprivation and a known risk factor for depression. PI youth exhibited more depressive symptoms and experiences of discrimination than 95 comparison youth (non-adopted, NA) raised in their biological families in the United States. In the final regression model, there was a significant interaction between sleep quality and discrimination, such that at higher levels of sleep quality, the association between discrimination and depression symptoms was non-significant. Despite being cross-sectional, the results suggest that the risk of depression in PI youth involves post-adoption experiences that appear unrelated to the impacts of early deprivation on neurobiological processes associated with depression risk. It may be crucial to examine methods of improving sleep quality and socializing PI youth to cope with discrimination as protection against discrimination and microaggressions.

Associations between obesity and mental illness have been identified, but they are complex and bidirectional(1). Weight loss interventions have been proposed as a potential strategy to improve mental health in individuals with overweight or obesity, but the evidence remains inconclusive(2). Additionally, the role of specific foods in a weight loss diet and mental health outcomes is not well understood(3). This study aimed to explore the association between weight loss (with and without almonds) and self-administered psychological and sleep assessments, including the Profile of Mood States (POMS), the Perceived Stress Scale (PSS), the Zung Self-Rating Depression Scale (ZSDS), and the Pittsburgh Sleep Quality Index (PSQI). Participants (n = 140, 47.5 ± 10.8 years) with overweight or obesity (BMI: 30.7 ± 2.3 kg/m2) were randomised to an energy-controlled almond-enriched diet (AED) or nut-free diet (NFD). Psychological and sleep assessments were conducted at baseline, after 3 months of weight loss, and after 6 months of weight maintenance. Data were analysed using mixed-effects models and linear regression. For POMS, total mood disturbance score (TMDS) (60.2%, p = 0.01), fatigue-inertia (21.2%, p = 0.003), and vigor-activity (19.9%, p<0.001) improved over time (with no different between groups), with improvements associated with the magnitude of weight loss (TMDS: β = 0.059, p = 0.02; fatigue-inertia: β = 0.268, p = 0.016; vigor-activity: β=-0.194, p = 0.048). No significant changes were observed in tension-anxiety, depression-dejection, anger-hostility, or confusion-bewilderment. A significant group x time interaction (p = 0.048) was found for the PSS, which increased in the NFD group (10.1%) and decreased in the AED (1%) during the weight maintenance phase. No significant changes were observed for the ZSDS. The PSQI demonstrated significant improvement in both groups over time for sleep quality (11.3%, p<0.001), sleep latency (24.3%, p<0.001), sleep disturbance (39.2%, p = 0.04), and daytime dysfunction (290.4%, p<0.001), but not for sleep duration or habitual sleep efficiency. Summed scores, generating the global sleep score (GSS), demonstrated an overall significant improvement in both groups over time (33.5%, p<0.001), and these improvements were associated with weight loss (GSS: β = 0.863, p<0.001). The findings emphasise the importance of evaluating mental health outcomes in weight loss interventions and highlight the potential influence of weight management on mood and sleep quality. Further research is warranted to explore the impact of diet composition on perceived stress and other mental health outcomes.

The classification of internet gaming disorder (IGD) as a mental condition for further study in 2013 marked the emerging recognition of potential mental health issues associated with internet and gaming addiction. The COVID-19 pandemic and the rapid growth of gaming technology have combined to increase internet gaming, resulting in unhealthy lifestyle behaviors, poor sleep quality and psychological distress. Identifying the complex interplay between internet problem use, sleep disorders and psychological distress is crucial. However, it remains unclear how physical activity and self-compassion could improve sleep quality when individuals experience IGD symptoms. The current study, therefore, examined the relationships between IGD, sleep quality, self-compassion, physical activity and psychological distress using a path analysis approach. The study, targeting young adults (N = 283), found that physical activity played a significant role in connecting the variables and supporting the overall fit of the model. The results suggest that interventions targeting individuals with IGD should focus on promoting physical activity participation and developing self-compassion. Future research should continue to investigate the effectiveness of clinical interventions that incorporate self-compassion and physical activity counseling for individuals with IGD.