The Effects of Sleep Restriction on Biological, Psychological, and Neurocognitive Measures of Health

Chronic sleep restriction impacts a significant proportion of the population, even though health is optimized following a minimum of seven hours of sleep. A preponderance of the literature examining the effects of sleep loss focuses on males and total sleep deprivation. Sleep restriction paradigms provide more ecological validity, as they are more consistent with sleep loss characterized in epidemiological studies. Moreover, enhancing the understanding of sleep loss among women, who are generally the gender most likely to encounter negative health as a result of poor sleep quality, is crucial. Thus, this investigation aimed to examine sleep restriction amongst a female sample. Group assignment was determined on the basis of objective and subjective measures of sleep collected in the baseline phase. Participants were then placed in the Naturally Sleep Restricted (NSR) group (n = 11), or the Experimentally Sleep Restricted (ESR) group (n = 9). The ESR group was assessed on Day 1 and Day 7 (i.e., prior to and following sleep restriction). We hypothesized that following sleep restriction, the ESR group would exhibit decrements in biological, psychological, and neurocognitive functioning. We further hypothesized that relative to the ESR group at Day 1, the NSR group would exhibit reduced functioning. However, we hypothesized that the NSR participants would fare better compared to the ESR group at Day 7. Results indicated that following sleep restriction, the ESR group exhibited elevated IL-1β, anxiety, tension, and fatigue and a decrease in depression, anger, and reaction time. The NSR group evidenced elevated IL-6 relative to the ESR group at Day 1. Finally, relative to the NSR group, the ESR group at Day 7 exhibited elevated anxiety, tension, fatigue, confusion, and correct non-matches on a measure of working memory. Further, the ESR group at Day 7 evidenced lower levels of depression and anger relative to the NSR group. Generally, results indicate that volitional sleep restriction (NSR) produces a different constellation of outcomes relative to non-volitional sleep restriction (ESR). Future research should examine these variables with a larger sample size and over a longer period of sleep restriction in order to assess further changes in functioning

A Preliminary Comparison of Food Consumption, Appetite, and Exercise Self-Reports In Chronic and Experimental Sleep Restriction Groups

Introduction: Previous research has examined sleep restriction (SR) in relation to increased daily caloric intake, suggesting that chronic SR is a significant risk factor for weight gain and obesity. However, few studies have examined behavioral factors that contribute to this weight gain, and no studies have differentiated chronic SR vs. short term SR on these measures. We examined behavioral self-report measures among participants who engage in chronic natural sleep restriction (NSR) and participants who are experimentally sleep restricted (ESR) to elucidate these underlying differences. Methods: Twelve female participants completed a screening interview to assess for psychopathology and sleep disorders. Participants were then assigned to either an NSR (n=6) or ESR (n=6) group based on sleep diary measures and one week of actigraphy monitoring. NSR participants averaged less than 7 hours TST, and ESR participants averaged between 7–9 hours TST. ESR participants then decreased their TST by 90 minutes per night for 1 week. Self-reported behavioral measures evaluating food consumption, appetite, and exercise duration (vigorous, moderate, and light intensity) were collected for both groups during the monitoring week and for the ESR group during the experimental week. Results: Findings suggest no significant differences between ESR and NSR groups based on subjective measures of food consumption (U=17.5,n1 =n2 =6,p=.936) and appetite (U=7.5,n1 =n2 =6,p=.087) during monitoring week. No significant differences were observed between groups when comparing final day NSR ratings during monitoring week with final day ESR ratings during SR week for food consumption (Z=-.736, n=6,p=.461) or appetite (Z=-.816,n=6,p=.414). Lastly, no significant differences were found between groups based on self-reported exercise duration (vigorous intensity: NSRM=8.25,SD=6.43,ESRM=13.93,SD=13.54,t=-.928, moderate intensity: NSRM=10.44,SD=9.72,ESRM=11.43,SD=8.79,t=-.185, and light intensity: NSRM=49.14,SD=34.54,ESRM=26.67,SD=11.73,t=1.509; all p\u3e.18). Conclusion: Contrary to previous research examining these measures, no differences were found between the NSR and ESR groups. Results suggest that weight gain secondary to sleep restriction, both chronic and short term, may not be the result of behavioral changes. Given these preliminary non-significant findings, further evaluation of the sample is being conducted currently through an examination of changes in participant concentrations of ghrelin and leptin; which are hunger and satiety biomarkers. Support (If Any): NSU President’s Faculty Research and Development Grant

The Psychological and Physiological Implications of Sleep Restriction: A Comparison of Voluntary and Experimental Sleep Restriction Groups

Introduction: Sleep restriction (SR) has profound adverse effects on health and wellbeing; however, it isn’t clear if there are differential effects of chronic and voluntary SR vs. short-term and involuntary SR. In order to examine this possibility, we tested the extent to which psychological and physical health measures were influenced by a group of participants who voluntarily restricted their sleep (VSR) relative to participants who underwent 7 days of experimental SR (ESR). We tested a female-specific population since sleep complaints in women are particularly associated with impaired psychological functioning. Methods: Participants underwent a psychiatric interview in order to screen for psychopathology and existing sleep disorders. Upon study enrollment, sleep group categorization (ESR vs. VSR) was confirmed through sleep diary and actigraphy monitoring for 1 week. The VSR group slept less than 7 hours per night (actigraphy-verified) and ESR group was asked to sleep 90 minutes less than their average sleep time (actigraphy-verified). Participants in both groups completed clinical health measures and provided saliva samples for the quantification of IL-1β, IL-6, and cortisol. Results: Preliminary results suggest that ESR results in decreased psychological health including perceived stress (PSS: BL mean = 16.8, day 7 = 18.2), moodiness (POMS: BL mean = 0, day 7 = 26.6), and state anxiety (STAI: BL mean = 34.2, day 7 = 44.8). In addition, relative to baseline, measures of inflammation were increased with ESR (IL-6: BL mean = 18.98 pg/mL, day 7 = 41.83 pg/mL and IL-1β BL mean 38.06 pg/mL, day 7 = 87.76 pg/mL). Comparing VSR to ESR, we found that the ESR group reported worse psychological health and higher inflammation markers (IL-6 VSR mean = 15.70 pg/mL and ESR day 7 mean = 41.6 and IL-1β VSR mean = 32.10 pg/mL ESR day 7 mean = 87.76 pg/mL). Conclusion: We find that, consistent with previous reports, involuntary experimental SR (ESR) results in decreases in self-reported psychological health and increases in measures of inflammation. New to our study, we show that relative to people who voluntarily restrict their sleep (VSR), the psychological and physiological effects of ESR are more pronounced

Sleep Deprivation Results in Increased Expression of Cancer-Related MiRNAs in Humans

Introduction: A large and growing body of evidence shows that sleep loss has profound deleterious effects on health and has been specifically linked to the development of several cancers. Despite this obvious health cost, there is almost no current understanding of how sleep loss increases the risk for tumor development. The purpose of the present study was to identify epigenetic mechanisms through which total sleep deprivation (TSD) altered expression of known cancer-related genes (suppressors and promoters). To that end, we tested the effects of TSD on the expression of miRNAs that are associated with tumor development. Methods: Twenty-three participants (14 males, mean age = 20) underwent actigraphy-verified TSD for 24 hours in a controlled environment. miRNA preparations were extracted from participants’ plasma and processed for cDNA synthesis. The resulting cDNA pools were used as templates in qPCR reactions in an effort to estimate differential miRNA expression. Results: Results indicated that sleep deprivation caused significant differential expression of several specific miRNA tumor-related genes, including miR-15a, miR-96, and miR-296-5p. Accordingly, further tests were focused on these two miRNA species on a subset of participants. Results showed that, there was a significant upregulation of miR-15a (p \u3c 0.05), miR-96 (p \u3c 0.05), and miR-22 (p \u3c 0.05), but not miR-296-5p (p=0.12). Conclusion: Overall, these findings show how even short-term sleep loss can alter cancer-associated pathways. Increased expression of miR-15a and miR-22 have known tumor suppression properties. It is possible that miR-15a and miR-22 exert protective effects in response the TSD-induced disruption to homeostasis. Although miR-96 is a known oncogene, it is also part a complex clock gene signaling pathway with diurnal expression. Accordingly, TSD potentially disrupts the normal diurnal expression pattern miR-96. We are currently following up on these results in a study of people who regularly experience sleep loss (i.e. chronic sleep restriction). Support (If Any): This work is supported by the Department of Education. Number P120A1400

Catechol‐O‐Methyltransferase Val158Met Polymorphism Associates with Affect and Cortisol Levels in Women

Introduction We tested the extent to which the catechol‐O‐methyltransferase (COMT) Val158Met polymorphism is associated with affective state and evening cortisol levels. We limited our study to women as previous research suggests that the link between COMT genotype and psychological health is entangled by sex differences. Materials and Methods The participants were assessed on measures of anxiety, mood disturbance, depressive symptomatology, and perceived stress. We also evaluated participants on a quality of life measures that included two emotion domains and two physical domains (physical health and environment). Results We found that under normal (nonstress) conditions, the COMT A allele (Met carriers, higher dopamine) associates with healthier affect and lower afternoon cortisol levels in women. These effects were limited to affective measures and not to physical or environmental quality of life. Conclusions These findings help to shed light on the complex nature of COMT and emotion, and suggest that both sex and task condition (stress vs. nonstress) should be considered when examining the relationship between COMT genotype and emotion