According to data presented at ESC Congress 2022, adolescents who sleep less than eight hours per night are more likely to be overweight or obese than their peers who get enough sleep.
In the SI! Program for Secondary Schools trial including 1,229 teenagers in Spain, this study looked at the relationship between sleep duration and health. At baseline, the participants’ average age was 12 years old, and there were an equal number of boys and girls.
A combination of additional harmful traits, such as extra body fat in the centre, high blood pressure, and abnormal blood lipid and glucose levels were also more prevalent in shorter sleepers.
“Our study shows that most teenagers do not get enough sleep and this is connected with excess weight and characteristics that promote weight gain, potentially setting them up for future problems,” said study author Mr. Jesús Martínez Gómez, a researcher in training at the Cardiovascular Health and Imaging Laboratory, Spanish National Centre for Cardiovascular Research (CNIC), Madrid, Spain. “We are currently investigating whether poor sleep habits are related to excessive screen time, which could explain why older adolescents get even less sleep than younger ones.”
At ages 12, 14, and 16, each participant had their sleep three times throughout the course of a seven-day period recorded by a wearable activity tracker. The American Academy of Sleep Medicine recommends that children aged 6 to 12 sleep between nine and twelve hours per night and children aged thirteen to eighteen between eight and ten hours. The study employed 8 hours or more as the ideal amount of time to simplify the analysis. Participants were categorised as very short sleepers (less than 7 hours), short sleepers (7 to 8 hours), and optimal (8 hours or more).
Body mass index was used to evaluate if a person was overweight or obese. The waist circumference, blood pressure, blood glucose, and cholesterol levels were used to produce a continuous metabolic syndrome score ranging from negative (healthier) to positive (unhealthier) values.
Only 34% of participants aged 12 to 14 and 33% of participants aged 15 to 16 reported sleeping for at least 8 hours every night. Boys typically slept less than girls. Teenagers who slept the most also had better-quality sleep, which meant that they woke up less frequently during the night and spent more time in bed sleeping than those who slept less. The prevalence of overweight/obesity was 27%, 24% and 21% at 12, 14 and 16 years of age, respectively.
After controlling for parental education, parental migrant status, moderate-to-vigorous physical activity, smoking status, caloric intake, city (Madrid or Barcelona), and school, associations between sleep duration, overweight/obesity, and metabolic syndrome score were examined.
At ages 12 and 14, respectively, overweight/obesity was 21% and 72% more likely in extremely short sleepers compared to optimum sleepers. At 12 and 14 years old, short sleepers had a 19% and 29% higher likelihood of being overweight or obese than optimum sleepers, respectively. In a similar vein, when compared to people who sleep well, both very short and short sleepers had higher average metabolic syndrome scores at 12 and 14 years old.
Mr. Martínez Gómez said: “The connections between insufficient sleep and adverse health were independent of energy intake and physical activity levels, indicating that sleep itself is important. Excess weight and metabolic syndrome are ultimately associated with cardiovascular diseases, suggesting that health promotion programmes in schools should teach good sleep habits. Parents can set a good example by having a consistent bedtime and limiting screen time in the evening. Public policies are also needed to tackle this global health problem.”
Parvathy Sukumaran 
