Adequate sleep is important for children's cardiometabolic health

Even the youngest members of our society, the children who represent the cornerstone of our future sustainability, are displaying troubling trends with insufficient sleep duration. Notably, research conducted by the Centers for Disease Control and Prevention in the United States revealed that 34.7% of children aged 3–17 years had inadequate sleep. According to parental reports, this was most common (37.5%) in children aged 6–12 years.1 The sleep duration guidelines established by the American Academy of Sleep Medicine define insufficient sleep as less than 10 h for children aged 3–5 years, less than 9 h those aged 6–12 years and less than 8 h for those aged 13–17 years.2 Over the last few decades, there have been significant lifestyle shifts due to the increased daily use of electronic media devices. These have become an integral part of young people's lives, as children are now growing up immersed in these devices. Unfortunately, this may also partly explain why certain studies have observed that prepubescent children are going to bed later and may not be getting the recommended hours of sleep each night. For example, a study of Finnish children aged 10–11 years indicated that computer use, television viewing and the presence of media in children's bedrooms could reduce sleep duration and delay bedtimes.3 There have been well-documented associations between chronically inadequate sleep duration and consistently late bedtimes and various adverse health outcomes in adults, such as type 2 diabetes4 and cardiovascular disease.5 These findings raise concerns about the potential impact of similar nocturnal habits on children's health. This issue of Acta Paediatrica contains a paper by Nilsson et al, who addressed this concern by conducting a cross-sectional investigation of 411 nine-year-old children in Sweden.6 Their aim was to explore whether sleeping less than the recommended duration of 9 h per day, and going to bed at the population median of 9.39 pm or later, would be correlated with an increased risk of adverse cardiometabolic outcomes. Nilsson et al's research serves as a poignant reminder of the pivotal role that sleep plays in the cardiometabolic health of children. It found that children who slept for 9–11 h per day, and retired to bed early, had a more favourable cardiometabolic profile. This was evidenced by a lower cardiovascular risk score for metabolic syndrome, compared to those who slept for less than 9 h and went to bed late. Notably, Nilsson et al. used a cluster of adverse metabolic markers as indicators of central adiposity. These included high blood concentrations of triglycerides, cholesterol, glucose and high blood pressure, which have been associated with increased cardiovascular outcomes in children and adolescents.7 Crucially, the Nilsson et al.'s study also found that the time that the subjects went to bed was a determinant for cardiometabolic health. Even after factoring in total sleep duration, a late bedtime was associated with a significantly higher risk score for metabolic syndrome than an early bedtime. Based on the findings by Nilsson et al., it could be hypothesised that prioritising sufficient sleep duration and earlier bedtimes among prepubescent children could hold some promise for improving cardiometabolic health both in the short and long term. However, further studies are needed to investigate how sleep duration and bedtimes affect other cardiometabolic outcomes among prepubescent children. These include cardiac electrophysiology and 24-h blood pressure profiles. Another intriguing question that needs to be resolved is whether strategies that extend sleep duration and establish early bedtimes could improve the health of children with metabolic syndrome. It is noteworthy that sleep duration and the time that children go to bed are not the only relevant factors. Sleep regularity and sleep quality are just as important for overall health, including cardiometabolic outcomes, as demonstrated by adult studies.8, 9 Furthermore, Nilsson et al. did not screen for paediatric obstructive sleep apnoea in their study, which can, for instance, be caused by adenotonsillar hypertrophy among children. Obstructive sleep apnoea can lead to a variety of adverse cardiometabolic outcomes in children and adolsecents.10 Hence, future studies should also screen participating children for obstructive sleep apnoea when studying the effects of sleep on cardiometabolic health. One clear takeaway from Nilsson et al.'s findings is the critical importance of instilling and maintaining healthy sleep habits from childhood. This requires a multi-faceted approach, which engages parents and other caregivers, healthcare professionals, policymakers, and involves public health initiatives. Essential components include establishing consistent bedtime routines, minimising screen time before sleep and cultivating a conducive sleep environment. For instance, parents can play a pivotal role, by creating calming bedtime rituals and fostering an environment conducive to restful sleep. Healthcare professionals can offer guidance to parents, by emphasising age-appropriate sleep duration and the significance of regular sleep schedules. Public health campaigns can play a vital role in raising awareness among parents, educators and healthcare providers about the profound impact of sleep on overall health and well-being. By collaboratively addressing these factors, we can empower children to develop healthy sleep patterns early in life, which will establish the foundations for lifelong well-being. While Nilsson et al.'s findings provide valuable insights into the broader benefits of sleep, it is essential to approach their conclusions with caution and balance. Health outcomes are influenced by multiple factors and sleep is just one component. Following a healthy diet, regular physical activity, minimising sedentary behaviour and creating a safe environment are all critical aspects of paediatric health, including cardiometabolic outcomes.11 Therefore, while sleep plays a crucial role, a holistic approach is necessary to promote overall well-being in children. To conclude, Nilsson et al.'s research suggests that a child's health requires a nurturing environment, balanced nutrition, ample physical activity, sensible bedtimes and sound sleep. It is the harmonious combination of these sleep and health-related elements that cultivate vibrant health and well-being in our children. The responsibility for improving children's sleep duration is not just down to the children themselves. As adults and caregivers, we are responsible for monitoring our behaviour and creating an environment that is conducive to fostering children's health and well-being. Pei Xue: Conceptualization; funding acquisition; writing – original draft. Christian Benedict: Funding acquisition; supervision; writing – review and editing. None. The authors have no conflicts of interest to declare.