Impact of Sleep on Adolescent Cognitive Health with Higher Body Fat

The Link Between Sleep and Cognitive Function

Insufficient sleep has been increasingly linked to poorer cognitive function, particularly in adolescents. This connection becomes even more significant when considering adolescents with higher levels of body fat. According to a recent study published in JAMA Neurology, teens with overweight or obesity are more susceptible to cognitive declines related to poor sleep compared to their peers with normal weight.

Understanding the Research

Researchers at the University of Alabama at Birmingham spearheaded this investigation. They aimed to explore the influence of sleep on cognitive performance and how this relationship is affected by the adolescents' weight status. The team focused on exploring why weight status impacts cognitive functions and assessed the role of sleep within this dynamic.

The study utilized a single-blind, randomized, crossover trial method carried out from September 2020 to October 2022. The key measures involved Body Mass Index (BMI) and total body fat percentage, which helped the researchers gauge adiposity and its connection with cognitive abilities.

Key Findings

For their analysis, the research team included 61 adolescents, with an average age of 16 years and comprising 57.4% girls. These participants were exposed to either a restricted sleep period of 4 hours or an adequate sleep period of 8 hours after a baseline period of regular sleep.

Cognitive function was evaluated using the NIH Cognitive Toolbox composite scores. This tool measured various cognitive domains, such as attention, cognitive flexibility, and processing speed. The results indicated that adolescents with higher adiposity levels exhibited poorer cognitive performance following restricted sleep.

Differences Based on Weight Status

When the researchers compared cognitive outcomes during sleep restriction, adolescents with higher BMIs or total body fat percentages showed significantly weaker scores in global cognition, fluid cognition, attention, and cognitive flexibility than their normal-weight counterparts. This pattern was consistent even when different adiposity benchmarks were used.

The Role of Body Fat Percentage

The study also identified that higher body fat percentage thresholds were required to show significant cognitive declines compared to traditional pediatric obesity cutoffs. This finding highlights an increased risk for cognitive impairment due to poor sleep particularly for adolescents categorized under obesity or severe obesity.

Societal Implications

Aaron D. Fobian, PhD, an associate professor at the University of Alabama at Birmingham and a co-author of the study, emphasized the commonality of sleep restriction among teenagers. Given the shift in circadian rhythms during adolescence, teens are more prone to reduced sleep, particularly on school nights.

Interestingly, when adequately rested, no cognitive differences were noted between adolescents with healthy weight and those with overweight or obesity—a finding that diverges from some previous research.

Recommendations for Adolescents

Lindsay M. Stager, the study's lead author, underscored the importance of maintaining healthy sleep durations for teens with higher adiposity since they are more vulnerable to the adverse effects of insufficient sleep. She also encouraged advocating for societal changes, such as later school start times, to help adolescents achieve better sleep.