A recent study has found that adolescents who are overweight or obese are more susceptible to cognitive impairments following sleep restriction compared to their peers with healthy weight. This research was published in JAMA Neurology.
Previous research has established a link between pediatric obesity and cognitive difficulties, such as impaired executive function. Poor sleep has also been associated with increased adiposity (having a lot of body fat) and impaired cognition. However, the mechanisms underlying these associations have remained unclear.
Led by Lindsay M. Stager, researchers from the University of Alabama at Birmingham aimed to investigate the effects of adiposity and sleep on adolescent cognitive function.
“Research demonstrates a relationship between weight and cognition. We wanted to better understand the factors precipitating and sustaining that relationship. As sleep is directly tied to both weight and cognitive function, we were interested in its possible role in supporting the relationship between these two constructs,” explained Stager, a doctoral candidate.
Stager and her colleagues began by recruiting 61 adolescents aged 14 to 19 years.Questionnaires were administered on demographics and eating behaviors. Following this, adiposity was measured using body mass index (BMI) as well as total body fat percentage (TBF%), which categorized the participants into having a healthy weight (31 adolescents) and being overweight or obese (30 adolescents).
The study involved two sleep conditions: adequate sleep, with an average duration of 8 hours and 54 minutes, and restricted sleep, with an average duration of 4 hours and 12 minutes. After each sleep condition, the adolescents underwent cognitive assessments to evaluate several aspects of their cognition.
This included global cognition (overall indication of how well the brain functions), fluid cognition (ability to solve new problems and use logic in new situations), cognitive flexibility (brain’s ability to handle thinking about multiple concepts at once), working memory (the brain’s ability to temporarily hold and work with information), episodic memory (memories of specific events in life), attention (ability to focus on a task without getting distracted), as well as processing speed (how quickly the brain can understand and react to information).
The findings revealed that restricted sleep led to poorer global cognition, fluid cognition, and cognitive flexibility in adolescents who were overweight or obese, compared to adequate sleep. In contrast, no significant differences in cognitive performance were observed for adolescents with healthy weight between the two sleep conditions.
Adolescents who were obese or overweight also had significantly lower attention scores following restricted sleep when compared to their peers with healthy weight who also had restricted sleep.
“Adolescents with elevated adiposity were impacted by just one night of short sleep,” said co-author Aaron Fobian, an associate professor of psychiatry and behavioral neurobiology. “Research has demonstrated that sleep duration can affect cognition, and with longer sleep deprivation, adolescents with healthy weight would likely show impaired cognitive as well.”
“However, our study suggests that adolescents with elevated adiposity are more sensitive to poor sleep than those with healthy weight. Due to early school start times, obtaining one night of short sleep is something that most adolescents experience very frequently. Thus, this is something that is likely affecting adolescents on a regular basis.”
No differences were evident following adequate sleep for either group.
“Poor sleep is extremely common among adolescents,” Stager told PsyPost. “This study highlights the importance of promoting healthy sleep among adolescents and shows us that individuals with elevated adiposity may be more strongly impacted by social and environmental structures which limit adolescents’ abilities to obtain adequate sleep (i.e., early school start times).”
Overall, the study underscores the importance of adequate sleep for adolescents, particularly those with overweight or obesity. However, the study had some limitations. For instance, the at-home sleep conditions may have introduced variability in participants’ sleep duration and environment.
“It is important to note that we saw increased cognitive vulnerability to restricted sleep after just one night of sleep restriction and it is common for teens to have multiple nights of poor sleep each week,” Stager noted. “Thus, it will be important to assess whether these negative cognitive effects are compounding with multiple nights of poor sleep.”
“The long term goal of this research is to better understand the negative health impacts of poor sleep and leverage this knowledge to build health interventions for teens that promote improved health outcomes and equity across more vulnerable groups,” she added.
The study, “Effect of Sleep Restriction on Adolescent Cognition by Adiposity”, was authored by Lindsay M. Stager, Caroline S. Watson, Edwin W. Cook III, and Aaron D. Fobian.