Browsing by Subject "sleep"

Objectives: Sleep is sensitive to mental stress. Mental stress can be triggered by everyday psychosocially stressful life events evoking feelings of fear of social evaluation, social exclusion or pressure of attaining desired goals. Deterioration of subsequent sleep is in turn widely associated with different mental health outcomes. Here we examine, whether psychosocial stress experienced before night sleep affects non-rapid eye movement (NREM) sleep architecture and sleep spindles. Furthermore, we intend to elucidate whether the effects of stress are different between two halves of the night. To our knowledge this is the first study integrating these themes and covering the entire night EEG measurement. Methods: Subjects were 20- to 34-year-old healthy adults (n=34) distributed into two experimental groups, completing different virtual reality scenarios. Subjects of stress condition performed a public speaking task in front of an attentive virtual audience whereas the subjects of control condition listened a neutral presentation in otherwise identical except empty virtual seminar room. Following both virtual reality scenarios participants’ sleep parameter data were gathered with electroencephalography (EEG) during the following night in the sleep laboratory. Results and Conclusions: We found that participants in stress condition displayed significantly lower N2 proportion during the first half of the night in contrast to control condition, accompanying slight reduction in N3 and REM sleep. Psychosocial stress had no significant effect on the entire night sleep spindle parameters, compared to non-stressful condition. However, a significant interaction between group and time on central spindle density was found, as a significant increase of central spindle density in the stress group from first to second half of sleep. Thus, we conclude that pre-sleep psychosocially stressful experience is associated with decreased N2 proportion during the first half of the sleep and increased central spindle density from the first to second half of the sleep, and the pattern is significantly different compared to sleep after neutral experience. These findings might indicate potential sleep homeostatic mechanism, whereby the stress related reduction of N2 sleep observed earlier in the night may be compensated for by a denser appearance of spindles later in the night, thus promoting sleep continuity and compensating for effects which occurred closer to the stressor.

Background and objectives: Since early adolescence, the bedtimes and wake-up times begin to delay gradually until the early adulthood. This so-called shift to eveningness reaches its maximum at around the age of 20, and it usually occurs earlier in girls than boys. Eveningness has been previously associated with depression, anxiety, sleep problems, somatic symptoms, and other health-related issues in adolescents and adults. The aim of this study is to examine the associations between adolescents’ chronotype and their physical and mental well-being. Methods: This study examined how the self-reported chronotype was associated with self-reported problems related to adolescents’ physical and mental well-being. The chronotypes were divided into 5 types: Definitive Morning-types, Moderate Morning-types, Intermediate-types, Moderate Evening-types, and Definitive Evening-types. The participants were 7th, 8th and 9th graders, and the sample consisted of 6522 students from 83 schools in Finland. Some of the data was gathered at three time points, some at two time points, and some at one time point during the academic year. The associations between chronotype and well-being variables were studied cross-sectionally and some of them also longitudinally. Results: The main findings were that eveningness was associated with difficulty concentrating in lessons, susceptibility to give up easily on difficult tasks, school burnout symptoms, feelings of nervousness and anxiety, excessive worrying, difficulty relaxing, irritability, restlessness, difficulty falling asleep, waking up at night, daytime tiredness, and low mood as compared to morningness. Eveningness was also associated with neck and shoulder pain, lower back pain, and headache, as well as pain in the head and lower back due to the use of digital devices. Eveningness was associated with decreased concentration in lessons and increased susceptibility to give up on difficult tasks across time. On the other hand, feeling lonely and not being accepted as part of the group were associated with morningness. Conclusions: In conclusion, the physical and mental health problems were emphasized among Evening-type adolescents, as compared to Morning-type adolescents. Since adolescents shift toward eveningness, the need for thorough management of sleep and circadian problems should be highlighted, in order to intervene and improve the mental and physical well-being of adolescents both at school and at home.

Aims. Human sleep is influenced by several biological and environmental factors. Furthermore, day-time experiences and emotion-related processes are likely to impact the subsequent sleep. However, it has been suggested that emotions may not have a direct impact on the quality or duration of sleep, but emotion regulation may have a noteworthy part in between. The aim of the present study is to investigate the effect of cognitive emotion regulation strategies on objectively measured sleep in adolescents. Ten distinct cognitive emotion regulation strategies and their association on sleep duration, sleep quality, regularity, and the timing of sleep phase was examined. The possible links between theoretically adaptive and maladaptive strategies and sleep were investigated as well. Methods. Sleep and cognitive emotion regulation strategies of 329 adolescents (67.1% girls, age M=17.47) were measured in SleepHelsinki!, a University of Helsinki –based research project. Sleep was measured objectively with actigraphy. Regression analyses were performed between distinct emotion regulation strategies and sleep outcomes, and between two composite variables (adaptive and maladaptive strategies) and sleep outcomes. Results and Conclusions. The average sleep duration of adolescents was 6.55 hours on weekdays and 7.41 hours on weekends, which is considerably less that the recommended 8-10 hours. A clear link between emotion regulation strategies and the timing of the sleep phase was found. The overall use of adaptive strategies as well as the use of distinct adaptive strategies was related to an earlier midpoint of the sleep phase on weekdays. Furthermore, the more rumination and catastrophizing were used, the later the sleep midpoint occurred. However, the link between emotion regulation strategies and duration, quality and regularity of sleep remains elusive. The results obtained in the present study suggest that the usage of various emotion regulation strategies is connected to the timing of nighttime sleep, particularly on weekdays. Sufficient emotion regulation is likely necessary for good nighttime sleep, but the adaptivity of the strategy may depend on complex person-, situation- or emotion-related matters.

Aims of the study. Previous studies have found that traumatic childhood experiences increase the risk of sleep problems in adulthood, but research in adolescence is scarce. Sleep problems negatively affect adolescents’ well-being, cognitive abilities and academic performance. The aim of this study was to examine how traumatic childhood experiences are associated with sleep in adolescence. Methods. This study was a part of SleepHelsinki! cohort study in the University of Helsinki. 305 adolescents aged 15-18 completed The Traumatic Experience Checklist (TEC) and sleep measurements including The Pittsburgh Sleep Quality Index (PSQI) and actigraphy measurements. Traumatic childhood experiences were categorized into emotional traumas, bodily traumas and sexual traumas. Connections between sleep variables and traumatic childhood experiences were examined and ordinal logistic regression was used for the statistical analyses that included the impact of the experience and the age of onset. Results and conclusions. Traumatic childhood experiences had a statistically significant association with sleep problems, but the connection was not discovered regarding objectively measured sleep timing and duration. Similar associations were discovered for boys and girls. Sleep problems were worse the more traumatic experiences adolescent had experienced. This study did not find this association to be affected by age of onset or impact of the traumatic event. Results of this study indicate that traumatic childhood experiences are a risk factor for sleep problems in adolescence.

Melatonin is a circadian regulatory hormone with neuroprotective properties. We have previously demonstrated the association of genetic variant rs12506228 near the melatonin receptor 1A gene (MTNR1A) with intolerance to shift work. Furthermore, this variant has been connected to Alzheimer’s disease. Because of the previously suggested role of melatonin signalling in foetal neurocognitive and sleep development, we studied here the association of rs12506228 with early development. The study sample comprised 8-month-old infants from the Finnish CHILD-SLEEP birth cohort (n=1301). Parental questionnaires assessed socioemotional, communication and motor development, as well as sleep length and night awakenings. The A allele of rs12506228 showed an association with slower socioemotional (P=0.025) and communication (P=0.0098) development but no direct association with sleep. However, the association of the Finnish seasons with infant sleep length interacted with rs12506228. Taken together, rs12506228 near MTNR1A, which has been previously linked to adult and elderly traits, is shown here to associate with slower early cognitive development. In addition, these results suggest that the darker seasons associate with longer infant sleep time, but only in the absence of the rs12506228 AA genotype. Since the risk allele has been connected to fewer brain MT1 melatonin receptors, these associations may reflect the influence of decreased melatonin signalling in early development.