Abstract Title: Benefits of napping and an extended duration of recovery sleep on alertness and immune cells after acute sleep restriction. Abstract Source: Brain Behav Immun. 2011 Jan ;25(1):16-24. Epub 2010 Aug 8. PMID: 20699115 Abstract Author(s): Brice Faraut, Karim Zouaoui Boudjeltia, Michal Dyzma, Alexandre Rousseau, Elodie David, Patricia Stenuit, Thierry Franck, Pierre Van Antwerpen, Michel Vanhaeverbeek, Myriam Kerkhofs Article Affiliation: Sleep Laboratory, (ULB 222 Unit), CHU de Charleroi, A. Vésale Hospital, Université Libre de Bruxelles, Montigny-le-Tilleul, Belgium. Abstract: Understanding the interactions between sleep and the immune system may offer insight into why short sleep duration has been linked to negative health outcomes. We, therefore, investigated the effects of napping and extended recovery sleep after sleep restriction on the immune and inflammatory systems and sleepiness. After a baseline night, healthy young men slept for a 2-h night followed by either a standard 8-h recovery night (n=12), a 30-min nap (at 1 p.m.) in addition to an 8-h recovery night (n=10), or a 10-h extended recovery night (n=9). A control group slept 3 consecutive 8-h nights (n=9). Subjects underwent continuous electroencephalogram polysomnography and blood was sampled every day at 7 a.m. Leukocytes, inflammatory and atherogenesis biomarkers (high-sensitivity C-reactive protein, interleukin-8, myeloperoxidase, fibrinogen and apolipoproteins ApoB/ApoA), sleep patterns and sleepiness were investigated. All parameters remained unchanged in the control group. After sleep restriction, leukocyte and - among leukocyte subsets - neutrophil counts were increased, an effect that persisted after the 8-h recovery sleep, but, in subjects who had a nap or a 10-h recovery sleep, these values returned nearly to baseline. Inflammatory and atherogenesis biomarkers were unchanged except for higher myeloperoxidase levels after sleep restriction. The increased sleepiness after sleep restriction was reversed better in the nap and extended sleep recovery conditions. Saliva cortisol decreased immediately after the nap. Our results indicate that additional recovery sleep after sleep restriction provided by a midday nap prior to recovery sleep or a sleep extended night can improve alertness and return leukocyte counts to baseline values. Article Published Date : Jan 01, 2011

Abstract Title: Daytime napping after a night of sleep loss decreases sleepiness, improves performance, and causes beneficial changes in cortisol and interleukin-6 secretion. Abstract Source: Am J Physiol Endocrinol Metab. 2007 Jan;292(1):E253-61. Epub 2006 Aug 29. PMID: 16940468 Abstract Author(s): A N Vgontzas, S Pejovic, E Zoumakis, H M Lin, E O Bixler, M Basta, J Fang, A Sarrigiannidis, G P Chrousos Article Affiliation: Penn State Univ. College of Medicine, Dept. of Psychiatry H073, 500 University Dr., Hershey, PA 17033, USA. This email address is being protected from spambots. You need JavaScript enabled to view it. Abstract: Sleep loss has been associated with increased sleepiness, decreased performance, elevations in inflammatory cytokines, and insulin resistance. Daytime napping has been promoted as a countermeasure to sleep loss. To assess the effects of a 2-h midafternoon nap following a night of sleep loss on postnap sleepiness, performance, cortisol, and IL-6, 41 young healthy individuals (20 men, 21 women) participated in a 7-day sleep deprivation experiment (4 consecutive nights followed by a night of sleep loss and 2 recovery nights). One-half of the subjects were randomly assigned to take a midafternoon nap (1400-1600) the day following the night of total sleep loss. Serial 24-h blood sampling, multiple sleep latency test (MSLT), subjective levels of sleepiness, and psychomotor vigilance task (PVT) were completed on the fourth (predeprivation) and sixth days (postdeprivation). During the nap, subjects had a significant drop in cortisol and IL-6 levels (P<0.05). After the nap they experienced significantly less sleepiness (MSLT and subjective, P<0.05) and a smaller improvement on the PVT (P<0.1). At that time, they had a significant transient increase in their cortisol levels (P<0.05). In contrast, the levels of IL-6 tended to remain decreased for approximately 8 h (P = 0.1). We conclude that a 2-h midafternoon nap improves alertness, and to a lesser degree performance, and reverses the effects of one night of sleep loss on cortisol and IL-6. The redistribution of cortisol secretion and the prolonged suppression of IL-6 secretion are beneficial, as they improve alertness and performance. Article Published Date : Jan 01, 2007