Adolescents who do not get enough sleep are more likely to be overweight or obese, new research has found.

According to the findings that were presented at the European Society of Cardiology (ESC) Congress 2022, those who sleep less than eight hours a night are more likely to be overweight or obese compared to adolescents who get enough sleep.

The Spanish study involved over 1,200 adolescents. Sleep was measured for seven days using a wearable activity tracker at three different periods in time – when the participants were 12, 14 and 16 years old.

The researchers noted that according to the American Academy of Sleep Medicine, children aged between six and 12 years are recommended to get between nine and 12 hours of sleep per night, while those aged 13-18 should be getting between eight and 10 hours nightly.

For this study, sleepers were put into one of three categories:

-Very short sleepers (less than seven hours of sleep per night)

-Short sleepers (seven to eight hours per night)

-Optimal (eight hours or more).

Body mass index was used to determine overweight and obesity and the researchers also calculated a continuous metabolic syndrome score ranging from negative (healthier) to positive (unhealthier) values that included waist circumference, blood pressure, blood glucose levels and lipid levels.

The study found that at the age of 12, just 34% of participants were getting at least eight hours of sleep per night. By age 14, this had dropped to 23%, while at 16 years of age, it had fallen further to 19%.

The prevalence of overweight/obesity was 27%, 24% and 21% at 12, 14 and 16 years of age respectively.

Associations between sleep duration, overweight/obesity and metabolic syndrome score were analysed after adjusting for potentially influencing factors, such as parental education, moderate-to-vigorous physical activity, smoking status, energy intake and school.

The study found that compared with optimal sleepers, overweight/obesity was 21% more likely in very short sleepers at the age of 12. By the age of 14, this had jumped to 72%.

Short sleepers were 19% more likely to be overweight/obese compared with optimal sleepers at the age of 12 and this increased to 29% among 14 year-olds.

Furthermore, both very short and short sleepers had higher average metabolic syndrome scores at 12 and 14 years compared with optimal sleepers. For example, they were more likely to have elevated blood pressure and abnormal blood lipid and glucose levels.

According to the study’s lead author, Jesús Martínez Gómez of the Spanish National Centre for Cardiovascular Research in Madrid, 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,” he said.

He added that the study shows that overall, “most teenagers do not get enough sleep”.

“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,” he added.

ESC Congress 2022 is taking place in Barcelona and online.