Teenagers who sleep less than eight hours at night are more likely to be overweight or obese than their peers who get enough sleep, according to a study.

Shorter sleepers are also more likely to have a combination of other negative characteristics, such as abdominal obesity, high blood pressure, and abnormal blood cholesterol and glucose levels. This study examined the association between sleep duration and health in 1,229 adolescents in the SI! Program for Secondary Schools trial in Spain.

2 Participants had an average age of 12 years at baseline with equal numbers of boys and girls. Sleep was measured for seven days with a wearable activity tracker three times in each participant at ages 12, 14 and 16 years.

For optimal health, the American Academy of Sleep Medicine advises sleeping 9 to 12 hours a night for 6 to 12 year-olds and 8 to 10 hours for 13 to 18 year-olds. To simplify the analysis, the study used 8 hours or more as optimal. Participants were categorised as very short sleepers (less than 7 hours), short sleepers (7 to 8 hours), and optimal (8 hours or more).