Less Sleep Leads to Overweight Kids

5 Jul 11, 12:00 a.m. | Comments (0)

A longitudinal study that observed 244 children from 3 to 7 years of age in Dunedin, New Zealand looked at how sleep duration affected body composition and the risk of becoming overweight. The study was published in the reputable BMJ on 26 June 2011.

Body mass index (BMI), fat mass, and fat free mass was measured along with accelerometry to measure physical activity and sleep duration. Questionnaires evaluated diet, television viewing and family factors.

Each additional hour of sleep was associated with 0.48 reduction in BMI and 0.39 lower risk of being overweight. This translates into a 61% reduction in the risk of being overweight or obese at age 7, for each extra hour of sleep. The reason is increased fat deposition in those who do not get enough sleep and it affects both boys and girls. Adjustment for diet and exercise did not change the impact other than increasing the confidence interval. The average time of sleep for the 3 to 5 year olds was 11 hours.

It is proposed that more time to eat, changed hormonal regulation (reduced leptin and increased ghrelin) causing increased hunger, reduced voluntary exercise and reduced thermoregulation might be the mechanisms.

Comment: Many studies now point to sleep as a major factor for child health (weight, blood pressure, attention, depression, learning, glucose regulation). This suggests that it may be more important even than exercise and diet. There is much research needed before we can answer all the questions with confidence but the message is clear: make sure that your children get enough quality sleep. Early to bed and early up seem better.

By Sven Hansen in Sleep

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