Excess weight and metabolic syndrome are associated with cardiovascular disease, suggesting that health promotion programs in schools should teach good sleep habits
Researchers from the National Center for Cardiovascular Research (CNIC) have found that adolescents who sleep less than eight hours are more likely to be overweight or obese than their peers who sleep enough. The results of this research are presented at the Congress of the European Society of Cardiology, ESC 2022, which is being held in Barcelona.
In addition, the study shows that those who sleep less were also more likely to have a combination of other unhealthy characteristics, including excess fat, high blood pressure, and abnormal blood lipid and glucose levels.
“Our study shows that most adolescents do not get enough sleep and that this is related to excess weight and characteristics that promote weight gain, which could lead to future problems,” explains the author of the study, Jesus Martinez Gomez, researcher at the CNIC’s Cardiovascular Health and Imaging Laboratory. “We are currently investigating whether poor sleep habits are related to excessive use of electronic devices, which could explain why older adolescents sleep even less than younger ones.”
Made within the YES Program!, a project of the SHE Foundation With the support of the “la Caixa” Foundation, the University of Barcelona and the CNIC, the research has examined the association between sleep duration and health in 1,229 adolescents in public secondary schools in Spain. The participants had an average age of 12 years at the beginning of the study, were evaluated for 4 years, and included approximately the same number of boys and girls.
The researchers measured sleep over seven days with a wearable activity tracker worn by each adolescent participant at ages 12, 14 and 16.
The American Academy of Sleep Medicine recommends 9 to 12 hours of sleep per night for children ages 6 to 12 and 8 to 10 hours for children ages 13 to 18 for optimal health.
Parents can set a good example by setting a consistent bedtime and limiting screen time at night
To simplify the analysis, the study used 8 hours or more as optimal. The participants were classified as very short sleepers (less than 7 hours), short sleepers (7 to 8 hours) and optimal (8 hours or more).
Overweight and obesity were determined according to body mass index.
The researchers calculated a continuous metabolic syndrome score ranging from negative (healthier) to positive (worse) values that included waist circumference, blood pressure, and blood glucose and lipid levels.
At age 12, only 34% of participants slept at least 8 hours a night, and this dropped to 23% and 19% at ages 14 and 16, respectively. Boys tended to sleep less.
Teenagers who slept more also had better quality sleep, meaning they woke up less during the night and spent a greater proportion of their time sleeping in bed compared to those who slept less. The prevalence of overweight/obesity was 27%, 24%, and 21% at 12, 14, and 16 years, respectively.
We analyzed the associations between the sleep duration, overweight/obesity and the metabolic syndrome score after adjusting for parental education, migrant status, moderate to vigorous physical activity, smoking status, energy intake, city (Madrid or Barcelona), and school.
Compared with optimal sleepers, overweight/obesity was a 21% and 72% more likely in very little sleepers at ages 12 and 14, respectively. those who they slept little they had 19% and 29% more than likely of being overweight/obese compared with optimal sleepers at 12 and 14 years, respectively. In addition, both very little and little sleepers had higher average metabolic syndrome scores at 12 and 14 years compared with optimal sleepers.
“The connections between poor sleep and poor health were independent of energy intake and physical activity levels, indicating that sleep itself is important,” he says. Rodrigo Fernandez-Jimenez, group leader of the Imaging and Cardiovascular Health laboratory. “Excess weight and metabolic syndrome are ultimately associated with cardiovascular disease, suggesting that health promotion programs in schools should teach good sleep habits.”
Thus, he concludes, “fathers and mothers can set a good example by setting a consistent bedtime and limiting screen time at night. Public policies are also needed to address this global health problem.”