Immune disruptions and night shift work in hospital healthcare professionals : the intricate effects of social jet-lag and sleep debt

Objectives: We aimed to examine the effects of circadian and sleep rhythm disruptions on immune biomarkers among hospital healthcare professionals working night shifts and rotating day shifts. Methods: Hospital nurses working either as permanent night shifters (n=95) or as day shifters rotating between morning and afternoon shifts (n=96) kept a daily diary on their sleep and work schedules over a full working week. Blood samples were collected at the beginning and end of the last shift during the week, and participants were categorized into three groups based on work shift: morning shift (39 day shifters sampled at 7:00 and 14:00), afternoon shift (57 day shifters sampled at 14:00 and 21:00), and night shift (95 night shifters sampled at 21:00 and 7:00). Circulating blood counts in immune cells, interleukin-6 and C-reactive protein concentrations as well as total sleep time per 24 hours during work days (TST24w) and free days (TST24f), sleep debt (TST24f — TST24w) and social jet-lag (a behavioral proxy of circadian misalignment) were assessed. Results: Compared with day shifters, night shifters had shorter sleep duration (TST24w=5.4 ± 1.4h), greater sleep debt (3.2 ± 1.4 h) and social jet-lag (6.7 ± 2.4 h). Variations of immune biomarkers concentrations were consistent with the expected diurnal variations among day shifters (i.e., low level in the morning, increase during the day, peak value in the evening). By contrast, in night shifters, blood concentrations of total lymphocytes, T-helper cells, cytotoxic T-cells, memory B-cells and interleukin-6 were lower at 21:00, increased during the night, and reached higher values at 7:00. Multivariate analyses ruled out significant impact of TST24w, sleep debt, and social jet-lag on immune biomarkers concentrations among day shifters. In contrast, among night shifters, multivariate analyses indicated a combined effect of total sleep time (TST24w), sleep debt and social jet-lag for total lymphocytes and T-helper cells but only a social jet-lag effect for interleukin-6 and a single total sleep time effect for neutrophil and B-Cells. Conclusions: Altogether, our results point to intricate response patterns of immune rhythms to circadian misalignment and sleep debt in night shifters. Specifically, these altered pattern expressions of immune cells may increase vulnerability to infections and reduce vaccination efficiency in night workers

Food restriction alters salivary cortisol and α-amylase responses to a simulated weightlifting competition without significant performance modification

Food restriction alters salivary cortisol and α-amylase responses to a simulated weightlifting competition without significant performance modificatio

Leukocyte Expression of Type 1 and Type 2 Purinergic Receptors and Pro-Inflammatory Cytokines during Total Sleep Deprivation and/or Sleep Extension in Healthy Subjects

The purinergic type P1 (adenosine A1 and A2A) receptors and the type P2 (X7) receptor have been suggested to mediate physiological effects of adenosine and adenosine triphosphate on sleep. We aimed to determine gene expression of A1R (receptor), A2AR, and P2RX7 in leukocytes of healthy subjects during total sleep deprivation followed by sleep recovery. Expression of the pro-inflammatory cytokines IL-1β and TNF-α were also determined as they have been characterized as sleep regulatory substances, via P2RX7 activation. Blood sampling was performed on 14 young men (aged 31.9 ± 3.9) at baseline (B), after 24 h of sleep deprivation (24 h-SD), and after one night of sleep recovery (R). We compared gene expression levels after six nights of habitual (22.30–07.00) or extended (21.00–07.00) bedtimes. Using quantitative real-time PCR, the amount of mRNA for A1R, A2AR, P2RX7, TNF-α, and IL-1β was analyzed. After 24 h-SD compared to B, whatever prior sleep condition, a significant increase of A2AR expression was observed that returned to basal level after sleep recovery [day main effect, F(2, 26) = 10.8, p < 0.001]. In both sleep condition, a day main effect on P2RX7 mRNA was observed [F(2, 26) = 6.7, p = 0.005] with significant increases after R compared with 24 h-SD. TNF-α and IL-1β expressions were not significantly altered. Before 24 h-SD (baseline), the A2AR expression was negatively correlated with the latency of stage 3 sleep during the previous night, while that of the A1R positively. This was not observed after sleep recovery following 24 h-SD. This is the first study showing increased A2AR and not A1 gene expression after 24 h-SD in leukocytes of healthy subjects, and this even if bedtime was initially increased by 1.5 h per night for six nights. In conclusion, prolonged wakefulness induced an up-regulation of the A2A receptor gene expression in leukocytes from healthy subjects. Significant correlations between baseline expression of A1 and A2A receptors in peripheral cells and stage 3 sleep suggested their involvement in mediating the effects of adenosine on sleep

Decrease in serum leptin after prolonged physical activity in men.

For effective total quality management (TQM), internal, process-related, as well as external, market-oriented, information is crucial. In particular, external marketing information seems to be very valuable since customers are the ultimate evaluators of the quality of an organization. In this paper, by adopting a services and relationship marketing perspective, we empirically study factors that influence the utilization of quality-related marketing research information by decisionmakers in organizations that strive to monitor and improve their quality levels. Our results show clearly that the use of quality-related information is most strongly influenced by the quality of informational contents. In addition, satisfaction with a specific quality-related research project functions as an important mediator between service quality of the project on the one hand and decision-maker trust in the provider and information use on the other hand. The results can be especially useful to marketing research agencies that strive to improve the quality of the service they deliver to organizations actively involved in the area of TQM

Hyperactivity of the Sympatho-Adrenomedullary System Without Any Modification of the Hypothalamic-Pituitary-Adrenal Axis After Food Restriction Among High-Level Weightlifters.

We examined the effects of 6 days of food restriction on salivary a-amylase (sAA), cortisol and dehydroepiandrostenedione (DHEA) awakening responses, psychological parameters and performance among 11 international weightlifters. Assessments were made at baseline (T-1) and 6 days after a normal period of training while maintaining body weight (T-2). Then, participants were assigned to 2 groups depending on whether they lost (Diet group) or maintained (Control group) their body mass. Anthropometric, psychological, physical, and physiological assessments were also realized 6 days (T-3) after the restricted dietary period for the Diet group. Food restriction (T-3) induced a significant rise of SAA awakening response (364.6%, p 0.05), whereas no significant variations were observed among the hypothalamic-pituitary-adrenal axis (cortisol and DHEA). Significant alterations of the general Recovery Score and General stress Score, evaluated through the Recovery-Stress Questionnaire for athletes, were noted after food restriction. Weightlifting performance, evaluated during a simulated weightlifting competition, was maintained after the 6-day food restriction; we even noted an increased weightlifting performance related to body mass (Sinclair coefficient). Our findings support the hypothesis that food restriction induces a challenging situation to the organism, resulting in an asymmetry between the 2 stress systems activation. These results reinforce the necessity to cautiously plan and monitor the weight regulation process before competition to avoid potential negative outcomes on psychophysiological parameters. In this regard, the psychobiological approach, especially the awakening responses, seems a useful tool

Hormonal and metabolic adaptation in professional cyclists during training

Mesure des concentrations de cortisol, testostérone, sulfate de déhydroépiandrostérone (sDHEA), des catécholamines et des acides aminés branchés chez 18 cyclistes professionnels après 2 périodes d'entraînement intensif

Exercice, immunoglobuline A salivaire et infections du tractus respiratoire

Revue de questions. Exercice physique, immunité des muqueuses, IgA salivaires et infections respiratoires chez les sportifs. effets de l'exercice aigu, chronique. Hormones du stress (catécholamines, cortisol) et IgA salivaires. Infections respiratoires et niveau d'activité physique, entraînement modéré, effort intense. Relations entre modifications immunitaires et signes clinique