According to the objective of the study, “The potential association between short sleep duration or sleep problems and childhood overweight has not been well described. The objective of this study was to test the independent associations of sleep duration and problems with overweight risk in children.”

In the study, the parents of 785 third-grade children, from around the United States, were surveyed about their sleep habits. Then, three years later, when the children were in the sixth grade, the parents were interviewed again. Over these three years, 18% of the children had become obese.

Lumeng’s team stated that this association (more sleep, less chance of becoming obese) is regardless of their body-mass-index (BMI), gender, socioeconomic status/maternal education, race, or home environment.

Lumeng stated, “Many children aren’t getting enough sleep, and that lack of sleep may not only be making them moody or preventing them from being alert and ready to learn at school, it may also be leading to a higher risk of being overweight.” [ScienceDaily.com]

The average amount of sleep for these third-grade children was 9.45 hours per night, while the average amount of sleep for the six-graders was 8.78 hours.

Lumeng’s team found that each additional hour of sleep that a child got (in sixth grade) each night related to a 20% less chance of becoming obese. In fact, the relationship was more noticeable in third grade, when an extra hour of sleep meant that the child had a 40% less chance of becoming obese three years later.