Sleep variability and regularity as contributors to obesity and cardiometabolic health in adolescence

Abstract

Objective: Adolescence is a developmental stage of critical changes in sleep and its circadian timing when the contribution of abnormal sleep variability (amount) and sleep regularity (timing) to obesity and its associated adverse cardiometabolic health outcomes appears to increase. The aim of this study was to summarize findings from studies conducted in adolescents examining both sleep variability and regularity in relation to obesity and cardiometabolic health. Gaps in research and potential causal pathways that future studies should examine are highlighted. Results: Nightly deviations in sleep duration and sleep midpoint appear to contribute to the development of obesity and associated adverse cardiometabolic outcomes in youth. Studies show that increased sleep variability and irregularity are associated with obesity, decreased physical activity, dysregulated eating and inadequate diet, metabolic dysfunction, impaired cardiac autonomic balance, and elevated blood pressure in adolescents. Conclusions: A stable circadian timing of sleep is essential to the overall physical well-being of youth. Emerging evidence supports that sleep variability and circadian misalignment, including sleep irregularity, contribute to adverse obesity-related health outcomes early on in adolescence. Future studies should focus on the underlying behavioral and biological mechanisms in the causal pathway between day-to-day deviations in the amount and timing of sleep and obesity.

Accelerometry‐assessed sleep clusters and cardiometabolic risk factors in adolescents

“…The underlying mechanism may involve sociocultural and biological influences. Adolescents within the sleep irregularity and variability cluster may have irregular breakfast behaviors, which were associated with higher TG [7,37]. Additionally, it may be explained by increased absorption of dietary lipids with increased de novo synthesis of TG in the liver or decreased ability to catabolize absorbed dietary fat in male individuals with sleep deprivation [38].…”

“…Duan et al also observed a relationship between short sleep and high TG (≥1.24 mmol/L) only in adolescent boys [36]. Furthermore, a recent review supported associations of greater sleep variability and irregularity with obesity and adverse cardiometabolic health in adolescence [7]. The underlying mechanism may involve sociocultural and biological influences.…”

“…Recently, the American Heart Association added sleep duration as the eighth metric to cardiovascular health's definition (Life's Essential 8) [4]. Besides sleep duration, other sleep characteristics, including sleep efficiency, timing, variability, regularity, and wake time, have also been associated with adolescent cardiometabolic health [5][6][7][8]. These sleep characteristics within an individual were mainly assessed independently; however, they tend to be correlated with each other [9].…”

Wake up! It's time to recognize the importance of sleep in metabolic health

“…Among youth, Morales‐Ghinaglia and Fernandez‐Mendoza reported on the influence of inconsistent sleep patterns across nights on metabolic disease risk and proposed standard definitions for different metrics of sleep regularity and variability [28]. The authors concluded that nightly deviations in both the timing and duration of sleep in adolescents related to adverse metabolic outcomes, and they put forth important next steps to elucidate the direct and indirect effects of night‐to‐night variability in sleep duration and irregularity of sleep timing.…”

Associations of actigraphy‐assessed sleep variables with adiposity and serum cardiometabolic outcomes in emerging adults

“…Recent reviews also reported that having a later sleep timing midpoint (i.e. wake‐time – ½ sleep duration), as well as greater day‐to‐day sleep duration and sleep timing variability are associated with greater adiposity and adverse cardiometabolic outcomes (Chaput et al, 2020; Morales‐Ghinaglia & Fernandez‐Mendoza, 2023). Consistent evidence suggests that emerging adults and college students with shorter sleep duration and/or poorer sleep quality have greater adiposity (Bailey et al, 2014; Fernström et al, 2020; Kahlhöfer et al, 2016; Krističević et al, 2018; Meyer et al, 2012; Peltzer & Pengpid, 2017; Quick et al, 2014; Sa et al, 2020; Vargas et al, 2014; Yang et al, 2020), but much of this evidence is limited to self‐reported sleep variables and/or using body mass index (BMI) as a single indicator of adiposity/obesity.…”