The importance of sleep for cognition in young adults is well established, but the role of habitual sleep behavior in cognition across the adult lifespan remains unknown. We examined the relationship between sleep continuity and total sleep time assessed with a sleep detection device and cognitive performance using a battery of tasks in young (n = 59, mean age = 23.05) and older (n = 53, mean age = 62.68) adults. Across age groups, higher sleep continuity was associated with better cognitive performance. In the younger group, higher sleep continuity was associated with better working memory and inhibitory control. In the older group, higher sleep continuity was associated with better inhibitory control, memory recall, and verbal fluency. Very short and very long total sleep time was associated with poorer working memory and verbal fluency, specifically in the younger group. Total sleep time was not associated with cognitive performance in any domains for the older group. These findings reveal that sleep continuity is important for executive function in both young and older adults, but total sleep time may be more important for cognition in young adults.
Summary
Aging is associated with changes in sleep and decline executive functions, such as task-switching and task preparation. Given that sleep affects executive function, age-related changes in executive function may be attributable to changes in sleep. The present study used a sleep detection device to examine whether wake time after sleep onset (WASO) and total sleep time (TST) moderated age differences in task-switching performance and participants' ability to reduce switch costs when given time to prepare. Participants were cognitively healthy (MMSE > 26) younger (n = 54; mean age = 22.9; 67.8% female) and older (n = 45; mean age 62.8; 71.1% female) adults. Using a task-switching paradigm, which manipulated preparation time, we found that smaller global switch costs were associated with lower WASO and longer TST. Greater preparation effects on local switch costs and adoption of a task-set were associated with lower WASO, though this effect was significant only in older adults when stratified by age group. This association was independent of inhibition and working memory abilities. The lack of interactions between sleep and age group indicated that age differences in switch costs were not moderated by better sleep. Our results suggest that young and older adults may benefit similarly from lower WASO and longer TST in overall performance, and individuals with less WASO are more likely to engage preparatory strategies to reduce switch costs and boost task-switching performance.
Background
The coronavirus disease pandemic is predicted to have adverse health effects on children and adolescents who are overweight or obese due to restricted school activity and stay-at-home orders. The purpose of this observational study was to determine the factors associated with weight gain in children and adolescents with overweight and obesity during coronavirus disease 2019 (COVID-19) lockdown.
Methods
Ninety-seven participants (sex- and age-specific body mass index (BMI) ≥ 85th percentile) were included. A baseline examination was conducted pre-COVID-19 (August 2019 to January 2020), and re-examination was performed post-lockdown (June to September 2020) and the results were compared. Correlation and regression analyses were conducted to investigate the association among changes in cardiometabolic markers and lifestyle behaviors with changes in BMI z-score.
Results
During the COVID-19 pandemic, an increase in BMI z-score (2.56 [2.01–2.94] to 2.62 [2.03–3.18]) was noticed in children and adolescents with obesity. Changes in cardiometabolic markers including liver enzymes, triglycerides (
r
= 0.398), leptin (
r
= 0.578), and adiponectin (
r
= −0.326), as well as muscular strength (
r
= −0.212), were correlated with the increase in BMI z-score. According to a multivariate regression analysis, changes in sedentary time (B = 0.016; 95% confidence interval [CI], 0.001–0.032) and fast-food consumption (B = 0.067; 95% CI, 0.013–0.122) were the lifestyle variables associated with BMI z-score increase.
Conclusion
Changes in lifestyle behaviors including fast-food consumption and sedentary time during the COVID-19 pandemic may be associated with weight gain. In order to prevent health-related risks in children and adolescents with obesity during the pandemic, it is important to maintain the level of physical activity and healthy dietary habits.
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