[Physical activity and sleep in Icelandic adolescents]

Sleep duration and social jetlag in healthy adolescents. Association with anxiety, depression, and chronotype: a pilot study

PURPOSE

Misalignment between sleep opportunity and chronotype preference during adolescence may affect sleep and mental health. The aim of this study was to objectively evaluate sleep duration and social jetlag (SJL) to observe if there is a relationship with anxiety, depression, or chronotype.

METHODS

Community based cohort study (n = 65) was conducted in Northern Europe. Participants recorded their sleep during the regular school schedule for 3 school nights and 2 free nights with FDA-cleared/EU Medical Device Directive (CE-02862) compliant home sleep test. They also completed validated questionnaires to assess (Morningness Eveningness Questionnaire; MEQ), sleepiness (Epworth Sleepiness Scale; ESS), and insomnia (Insomnia Severity Index; ISI), anxiety (General Anxiety Disorder-7; GAD-7), and depression symptoms (Beck's Depression Inventory-II; BDI-II). Data were collected during the last week of February and the first 2 weeks of March, 2023.

RESULTS

Average sleep duration on school nights was 7 h, 15 min, with 18% of participants on average sleeping ≥ 8 h. Average sleep onset was significantly later on free nights (1 hour, 47 minutes; p < 0.0001) causing a high prevalence of moderate-severe SJL, in 71% of participants. Evening chronotypes (prevalence 15.4%) fell asleep later on free nights, causing them to have significantly more SJL (2 hours, 58 minutes) than morning chronotypes (1 hour, 32 minutes) and intermediary chronotypes (1 hour, 36 minutes). Evening chronotypes also had more severe insomnia (ISI + 4.4, p = 0.006; + 4.0, p = 0.001) and greater depressive symptoms (BDI-II + 21.6, p < 0.0001; + 17.1, p < 0.0001). A significant negative correlation was observed between MEQ scores and ESS (r =  - 0.287; p = 0.001), ISI (r =  - 0.343, p < 0.0001), GAD-7 (r =  - 0.185, p < 0.0001), BDI-II (r =  - 0.501, p = 0.0001), and suicidal thoughts (r =  - 0.294, p = 0.017).

CONCLUSION

Adolescents are sleep-deprived and have a high prevalence of SJL that is positively correlated with depressive symptoms and evening chronotype. That evening chronotypes have shorter sleep duration, more severe SJL, and significantly more sleepiness and insomnia, anxiety, and depressive symptoms may indicate possible benefits in identifying this group with the aim to assist them in improving their sleep habits with potentially positive effects on mental health.

Changes in health-related lifestyle choices of university students before and during the COVID-19 pandemic: Associations between food choices, physical activity and health

The COVID-19 pandemic has had a profound effect on our lives and society, influencing both individuals' lifestyles and habits. Recent research shows that anxiety and loneliness have continued to rise, along with changes in food and lifestyle choices. The aim of the study was to investigate whether the pandemic influenced food choices and consumption of energy drinks, alcohol, fruits, and vegetables among first-year university students. Additionally, assessing the relationship between mental and physical health, physical activity, and food choices. A total of 128 male and 128 female first-year students at the University of Iceland were invited to answer an electronic questionnaire in January and early February 2021. A total of 118 students (54% men) participated in the study and valid answers were 115 (46% participation rate). Almost half of the students (44%) experienced that their food choices had worsened, while 14% reported an improvement, compared to before the pandemic. Consumption of caffeinated beverages increased for 26% of students, while 19% experienced a decrease. Just over half of the students reported not drinking alcohol (13%) or reduced consumption (41%). Participants who reported that their mental health had deteriorated or remained the same tended to spend less time on physical activity and experienced worsened food choices (p<0.05). Similarly, those who spent less or the same time on physical activity estimated that their food choices had deteriorated (p<0.05). The COVID-19 pandemic has had a significant impact on the lifestyles of university students and this study has revealed how lifestyle choices and mental health seem to be highly affected by one another. Additionally, the potentially harmful effects of excessive intake of energy drinks need to be enhanced. Interestingly, about 40% of the respondents in the current study drank less alcohol during the pandemic than prior to the pandemic, indicating a strong relationship between alcohol drinking and social gatherings. This study reveals the importance of educating young people on healthy lifestyle choices and the importance of mental health needs to be emphasised.

Screen Time and Body Image in Icelandic Adolescents: Sex-Specific Cross-Sectional and Longitudinal Associations

Studies of adolescent body image and screen use are mostly limited to girls, and longitudinal data are scarce. We examined cross-sectional and longitudinal associations between these variables in mid-adolescent boys and girls. Data was collected when participants were at age 15 and 17, by questionnaire and objective measurements (n = 152 had complete data). Sex-specific linear regression was used to explore cross-sectional and longitudinal associations of self-reported screen use (total use, and time spent in gaming, TV/DVD/internet-based watching and internet use for communication) and body image, adjusting for vigorous physical activity, symptoms of depression, and body composition. Screen time was negatively associated with body image at both time points, although more strongly at age 15, and for girls only. Gaming and TV/DVD/internet watching was more strongly associated with body image than internet use for communication. Girls with above median screen time at both ages had 14% lower body image score at age 17 than girls with below median screen time at both time points. Our results suggest that screen use is likely to play a role in the development of body dissatisfaction among adolescent females. Limiting screen time may, therefore, help to mitigate body dissatisfaction in adolescent girls.

Sleep Quality and Duration in European Adolescents (The AdolesHealth Study): A Cross-Sectional, Quantitative Study

Sleep is a vital element of adolescents' overall health; it influences their body and mind and thus affects their quality of life. Adequate sleep quality and duration are essential for maintaining optimal metabolic health and lowering the risk of developing several medical conditions, such as cardiovascular disease. The current study aimed to assess the perceived sleep quality and duration of 1717 European adolescents from three different European countries (Spain, Iceland and Estonia) aged 13- to 16-years (900 boys, 817 girls) using the Pittsburgh Sleep Quality Index (PSQI). A multivariate analysis of variance (MANOVA) was performed to examine differences between groups and two-factor analysis of variance (ANOVA) was used to analyze city and age differences. The probability of having poor sleep quality and duration was calculated by Odd-Ratio (OR). Our study found poor sleep quality in 44% of the boys and 53% of the girls, whereas 68% and 69%, respectively did not get the recommended hours of sleep (i.e., 8-10 h). No difference was found between adolescents from Estonia, Iceland and Spain regarding sleep duration. In contrast, Spanish and Estonian adolescents reported higher probabilities of having poor sleep quality. Finally, girls had a significantly higher probability of poor sleep quality than boys.

Less physical activity and more varied and disrupted sleep is associated with a less favorable metabolic profile in adolescents

Background

Sleep and physical activity are modifiable behaviors that play an important role in preventing overweight, obesity, and metabolic health problems. Studies of the association between concurrent objective measures of sleep, physical activity, and metabolic risk factors among adolescents are limited.

Objective

The aim of the study was to examine the association between metabolic risk factors and objectively measured school day physical activity and sleep duration, quality, onset, and variability in adolescents.

Materials and methods

We measured one school week of free-living sleep and physical activity with wrist actigraphy in 252 adolescents (146 girls), aged 15.8±0.3 years. Metabolic risk factors included body mass index, waist circumference, total body and trunk fat percentage, resting blood pressure, and fasting glucose and insulin levels. Multiple linear regression adjusted for sex, parental education, and day length was used to assess associations between metabolic risk factors and sleep and activity parameters.

Results

On average, participants went to bed at 00:22±0.88 hours and slept 6.2±0.7 hours/night, with 0.83±0.36 hours of awakenings/night. However, night-to-night variability in sleep duration was considerable (mean ± interquartile range) 0.75±0.55 hours) and bedtime (0.64±0.53 hours) respectively. Neither average sleep duration nor mean bedtime was associated with any metabolic risk factors. However, greater night-to-night variability in sleep duration and bedtime was associated with higher total body and trunk fat percentage, and less physical activity was associated with higher trunk fat percentage and insulin levels.

Conclusion

Greater nightly variation in sleep duration and in bedtime and less physical activity were associated with a less favorable metabolic profile in adolescents. These findings support the idea that, along with an adequate amount of physical activity, a regular sleep schedule is important for the metabolic health of adolescents.

Less screen time and more physical activity is associated with more stable sleep patterns among Icelandic adolescents

OBJECTIVES

Emerging evidence suggests that inconsistent sleep may affect physical and psychological health. Thus, it is important to identify modifiable determinants of sleep variability. Screen time and physical activity are both thought to affect sleep, but studies of their relationship to sleep variability using objective measures are lacking. We examined cross-sectional associations between these variables in mid-teen adolescents using objectively measured sleep and activity.

METHODS

Wrist-worn accelerometers were used to measure one week of sleep and activity in 315 tenth grade students (mean age 15.8y) from six Reykjavík compulsory schools. Participants reported their daily hours of screen time. Regression analysis was used to explore associations of screen time and physical activity with variability in duration, quality, and timing of sleep, adjusting for DXA-measured body fat percentage, parental education, and physical activity or screen time.

RESULTS

Screen time, especially game playing, was associated with variability in duration, timing, and quality of sleep, most strongly with variation in bedtime. Physical activity was inversely associated with variability in duration, timing, and quality of sleep, most strongly with variation in the number of awakenings. Boys had less stable sleep patterns and higher screen time than girls, and sex-specific associations of screen time with sleep variability parameters were significant for boys only.

CONCLUSIONS

Less screen time and more physical activity were independently associated with less sleep variability among mid-teen adolescents. Our results indicate that encouraging youngsters toward an active lifestyle with limited screen use may be important to achieve more consistent sleep.