Effects of acute sleep loss on leptin, ghrelin, and adiponectin in adults with healthy weight and obesity: A laboratory study.

OBJECTIVE: This study investigated whether blood concentrations of leptin, ghrelin, and adiponectin are affected by acute total sleep deprivation in a sex- and weight-specific manner. METHODS: A total of 44 participants (mean age 24.9 years; 20 women; 19 with obesity) participated in a crossover design, including one night of sleep deprivation and one night of sleep in the laboratory. After each night, fasting blood was collected. RESULTS: After sleep deprivation, fasting levels of leptin were lower (mean [SE], vs. sleep: 17.3 [2.6] vs. 18.6 [2.8] ng/mL), whereas those of ghrelin and adiponectin were higher (839.4 [77.5] vs. 741.4 [63.2] pg/mL and 7.5 [0.6] vs. 6.8 [0.6] µg/mL, respectively; all p < 0.05). The changes in leptin and adiponectin following sleep loss were more pronounced among women. Furthermore, the ghrelin increase was stronger among those with obesity after sleep loss. Finally, the sleep loss-induced increase in adiponectin was more marked among normal-weight participants. CONCLUSIONS: Acute sleep deprivation reduces blood concentrations of the satiety hormone leptin. With increased blood concentrations of ghrelin and adiponectin, such endocrine changes may facilitate weight gain if persisting over extended periods of sleep loss. The observed sex- and weight-specific differences in leptin, ghrelin, and adiponectin call for further investigation.

A weighted blanket increases pre-sleep salivary concentrations of melatonin in young, healthy adults.

Weighted blankets have emerged as a potential non-pharmacological intervention to ease conditions such as insomnia and anxiety. Despite a lack of experimental evidence, these alleged effects are frequently attributed to a reduced activity of the endogenous stress systems and an increased release of hormones such as oxytocin and melatonin. Thus, the aim of the present in-laboratory crossover study (26 young and healthy participants, including 15 men and 11 women) was to investigate if using a weighted blanket (~12% of body weight) at bedtime resulted in higher salivary concentrations of melatonin and oxytocin compared with a light blanket (~2.4% of body weight). We also examined possible differences in salivary concentrations of the stress hormone cortisol, salivary alpha-amylase activity (as an indicative metric of sympathetic nervous system activity), subjective sleepiness, and sleep duration. When using a weighted blanket, the 1 hour increase of salivary melatonin from baseline (i.e., 22:00) to lights off (i.e., 23:00) was about 32% higher (p = 0.011). No other significant differences were found between the blanket conditions, including subjective sleepiness and total sleep duration. Our study is the first to suggest that using a weighted blanket may result in a more significant release of melatonin at bedtime. Future studies should investigate whether the stimulatory effect on melatonin secretion is observed on a nightly basis when frequently using a weighted blanket over weeks to months. It remains to be determined whether the observed increase in melatonin may be therapeutically relevant for the previously described effects of the weighted blanket on insomnia and anxiety.

Acute sleep loss increases CNS health biomarkers and compromises the ability to stay awake in a sex-and weight-specific manner.

Night shift work impairs vigilance performance, reduces the ability to stay awake, and compromises brain health. To investigate if the magnitude of these adverse night shift work effects differs between sexes and weight groups, 47 men and women with either normal weight or obesity participated in one night of sleep and one night of total sleep loss. During the night of sleep loss, participants' subjective sleepiness, vigilance performance, and ability to stay awake during 2-min quiet wake with eyes closed were repeatedly assessed. In addition, blood was collected in the morning after sleep loss and sleep to measure central nervous system (CNS) health biomarkers. Our analysis showed that women were sleepier during the night of sleep loss (P < 0.05) and spent more time in microsleep during quiet wake testing (P < 0.05). Finally, higher blood levels of neurofilament light chain, a biomarker of axonal damage, were found among women in the morning after sleep loss (P < 0.002). Compared with normal-weight subjects, those with obesity were more prone to fall asleep during quiet wake (P < 0.05) and exhibited higher blood levels of the CNS health biomarker pTau181 following sleep loss (P = 0.001). Finally, no differences in vigilance performance were noted between the sex and weight groups. Our findings suggest that the ability to stay awake during and the CNS health biomarker response to night shift work may differ between sexes and weight groups. Follow-up studies must confirm our findings under more long-term night shift work conditions.

Effects of One Night of Forced Wakefulness on Morning Resting Blood Pressure in Humans: The Role of Biological Sex and Weight Status.

Permanent night shift work is associated with adverse health effects, including elevated blood pressure (BP) and hypertension. Here, we examined the BP response to one night of forced wakefulness in a sitting position in a cohort without night shift work experience. According to a counterbalanced crossover design, 47 young adults with either obesity (N = 22; 10 women) or normal weight (N = 25; 11 women) participated in one night of sleep and one night of forced wakefulness under in-laboratory conditions. Resting ankle and brachial arterial BP were assessed in the morning, i.e., the time of the day when adverse cardiovascular events peak. After forced wakefulness, diastolic and mean arterial BP were ~4 mmHg higher at the ankle site and ~3 mmHg higher at the brachial site than after regular sleep (p < 0.05). The increase in BP following overnight forced wakefulness was more pronounced among men vs. women and more significant for diastolic BP at both sites among participants with normal weight vs. those with obesity. If confirmed in larger cohorts, including 24 h BP monitoring, people with occupations involving night shifts might benefit from regular BP monitoring. Particular attention should be paid to possible sex- and weight-specific effects of night shift work on BP.

Association of Daily Eating Duration and Day-To-Day Variability in the Timing of Eating With Fatal Cancer Risk in Older Men.

Meal timing has significant effects on health. However, whether meal timing is associated with the risk of developing and dying of cancer is not well-researched in humans. In the present study, we used data from 941 community-dwelling men aged 71 years who participated in the Uppsala Longitudinal Study of Adult Men to examine the association of meal timing with cancer morbidity and fatal cancer. The following meal timing variables were derived from 7-day food diaries: (i) daily eating duration, i.e., the time between the first and last eating episode of an arbitrary day; (ii) the calorically weighted midpoint of the daily eating interval, a proxy of when the eating window typically occurs during an arbitrary day; and (iii) the day-to-day variability in the timing of eating. We also assessed the reported daily energy intake reliability using the Goldberg method. During a mean observational period of 13.4 years, 277 men (29.4%) were diagnosed with cancer. Furthermore, 191 men (20%) died from cancer during 14.7 years of follow-up. As shown by Cox regression adjusted for potential confounders (e.g., smoking status and daily energy intake), men with reliable dietary reports whose daily eating intervals were on average 13 h long had a 2.3-fold greater fatal cancer risk than men whose daily eating windows were on average about 11 h long. We also found that men with an average day-to-day variability in the timing of eating of 48 to 74 min had a 2- to 2.2-fold higher fatal cancer risk than those with the lowest average day-to-day variability in the timing of eating (i.e., 23 min). No clear associations were found in men with inadequate dietary reports, emphasizing the need to consider the reliability of dietary records in nutritional epidemiology. To fully unlock its potential, studies are needed to test whether recommendations to time-restrict the 24-h eating interval and reduce day-to-day variability in the timing of eating can meaningfully alter the risk of death due to cancer.

How Sleep-Deprived People See and Evaluate Others' Faces: An Experimental Study.

Background: Acute sleep loss increases the brain's reactivity toward positive and negative affective stimuli. Thus, despite well-known reduced attention due to acute sleep loss, we hypothesized that humans would gaze longer on happy, angry, and fearful faces than neutral faces when sleep-deprived. We also examined if facial expressions are differently perceived after acute sleep loss. Methods: In the present, within-subjects study, 45 young adults participated in one night of total sleep deprivation and one night with an 8-hour sleep opportunity. On the morning after each night, an eye tracker was used to measure participants' time spent fixating images of happy, angry, fearful, and neutral faces. Participants also evaluated faces' attractiveness, trustworthiness, and healthiness on a 100-mm visual analog scale. Results: Following sleep loss, participants struggled more fixating the faces than after sleep. The decrease in total fixation duration ranged from 6.3% to 10.6% after sleep loss (P<0.001). Contrary to our hypothesis, the reduction in total fixation duration occurred irrespective of the displayed emotion (P=0.235 for sleep*emotion interaction) and was also present for the upper (P<0.001) but not the lower part of the faces (except for the lower part of angry faces). Overall, faces were evaluated as less trustworthy (-2.6 mm) and attractive (-3.6 mm) after sleep loss (p<0.05). Discussion: Facial expressions are crucial for social interactions. Thus, spending less time fixating on faces after acute sleep loss may come along with several problems for social interactions, eg, inaccurate and delayed judgment of the emotional state of others. In addition, more negative social impressions of others may lead to social withdrawal in sleep-deprived humans.

Association between pet ownership and sleep in the Swedish CArdioPulmonary bioImage Study (SCAPIS).

Preliminary findings suggest that pets may impact the owner's sleep. By using data from the Swedish CArdioPulmonary bIoimage Study (SCAPIS) cohort, we aimed to investigate the association of pet ownership with the following self-reported sleep outcomes in 3788 to 4574 participants: (i) achieving the recommended daily sleep duration for adults (i.e., at least 7 h per day); (ii) sleep quality as measured by the Pittsburgh Sleep Quality Index (a score of > 5 indicating poor sleep quality); and (iii) difficulty falling or staying asleep. Sleep metrics were not associated with pet ownership, dog ownership, and dog walking when controlling the logistic regression for possible confounders (e.g., shift work, lack of social interaction, and chronic stress). In contrast, cat ownership was associated with a higher odds ratio of failing to achieve the recommended duration of 7 h of sleep per day (adjusted odds ratio [95% CI]:1.18 [1.02, 1.37] versus non-cat owners). Our findings suggest that certain pet groups might have a more significant impact on the owner's sleep than others. As the observed association between cat ownership and short sleep duration might be a chance finding, this observation should be seen as hypothesis-generating only.

The role of exercise-induced peripheral factors in sleep regulation.

BACKGROUND: Recurrently disrupted sleep is a widespread phenomenon in our society. This is worrisome as chronically impaired sleep increases the risk of numerous diseases that place a heavy burden on health services worldwide, including type 2 diabetes, obesity, depression, cardiovascular disease, and dementia. Therefore, strategies mitigating the current societal sleep crisis are needed. SCOPE OF REVIEW: Observational and interventional studies have found that regular moderate to intensive exercise is associated with better subjective and objective sleep in humans, with and without pre-existing sleep disturbances. Here, we summarize recent findings from clinical studies in humans and animal experiments suggesting that molecules that are expressed, produced, and released by the skeletal muscle in response to exercise may contribute to the sleep-improving effects of exercise. MAJOR CONCLUSIONS: Exercise-induced skeletal muscle recruitment increases blood concentrations of signaling molecules, such as the myokine brain-derived neurotrophic factor (BDNF), which has been shown to increase the depth of sleep in animals. As reviewed herein, BDNF and other muscle-induced factors are likely to contribute to the sleep-promoting effects of exercise. Despite progress in the field, however, several fundamental questions remain. For example, one central question concerns the optimal time window for exercise to promote sleep. It is also unknown whether the production of muscle-induced peripheral factors promoting sleep is altered by acute and chronic sleep disturbances, which has become increasingly common in the modern 24/7 lifestyle.

Meal timing and subjective sleep disturbances in older men.

Older adults often complain about sleep disturbances, such as difficulty falling asleep and difficulty maintaining sleep in the early morning hours. Here, we investigated whether meal timing is associated with sleep problems in a cohort of older Swedish men (n = 998, mean age 71). Each participant filled out a seven-day food diary used to determine the daily eating time window, daily eating midpoint, and meal timing variability (i.e., the variance in daily eating midpoints over seven days). Questionnaires were used to assess difficulty initiating sleep and difficulty maintaining sleep. As indicated by logistic regression adjusted for potential confounders (e.g., BMI, diabetes status), no significant associations were found between the meal timing parameters and subjective sleep problems (P ≥ 0.37). Similar results were obtained when restricting the analysis to adequate reporters of daily energy intake. Therefore, our findings suggest that meal timing variations do not contribute to subjective sleep problems in older men. Our results must be replicated in cohorts that also include women and other measures of sleep.

Shifts of Transfusion Demand in Cardiac Surgery After Implementation of Rotational Thromboelastometry-Guided Transfusion Protocols: Analysis of the HEROES-CS (HEmostasis Registry of patiEntS in Cardiac Surgery) Observational, Prospective Open Cohort Database.

OBJECTIVES: Rotational thromboelastometry (ROTEM)-guided transfusion algorithms in cardiac surgery have been proven to be successful in reducing blood loss in randomized controlled trials. Using an institutional hemostasis registry of patients in cardiac surgery (HEROES-CS), the authors hypothesized that the use of ROTEM-guided transfusion algorithms would save blood products and overall costs in cardiac surgery in every day practice. DESIGN: Observational, prospective open cohort database. SETTING: Single-center academic hospital. PARTICIPANTS: Cardiac surgery patients. INTERVENTIONS: Implementation of ROTEM-guided bleeding management. MEASUREMENTS AND MAIN RESULTS: A classical-guided algorithm and a ROTEM-guided algorithm were used for patient blood management in 2 cohorts. Primary outcome was the use and amount of blood products and hemostatic medication. Secondary outcomes were amount of rethoracotomies, length of stay, and 30-day mortality. Finally, costs and savings were calculated. The classical-guided cohort comprised 204 patients, and ROTEM-guided cohort comprised 151 patients. Baseline characteristics showed excellent similarities after propensity score matching of 202 patients. Blood loss was lower after ROTEM guidance (p < 0.001). Absolute risk reduction was 17% for red blood cells (p = 0.024), 12% for fresh frozen plasma (p = 0.019), and 4% for thrombocyte concentrates (p = 0.582). More tranexamic acid was given, but not more fibrinogen concentrate, while desmopressin was given less often. Hospital length of stay was reduced by an overall median of 2 and a mean of 4 days (p < 0.001). Mortality and rethoracotomy rates were not affected. Potential savings were about €4,800 ($5,630) per patient. CONCLUSIONS: Implementation of a ROTEM-guided transfusion algorithm in cardiac surgery patients reduced the use of blood products and hemostatic medication, hereby saving costs. Reductions in mortality and rethoracotomy rates could not be found.