Shortened nightly sleep may help explain the rise in childhood obesity because sleep deprivation can disrupt levels of key hormones that regulate appetite and suppress physical activity, an endocrinology researcher reports.
Encouraging longer nightly sleep among children and adolescents should be considered as a component in any antiobesity campaign, according to Dr. Shahrad Taheri of the University of Bristol, England (Arch. Dis. Child. 2006 Oct. 19 [epub doi:10.1136/adc.2005.093013]).
Parents should encourage earlier bedtimes and longer sleep by taking such measures as enforcing strict bedtimes and wake times; providing a quiet, dark, and relaxing bedroom environment; avoiding large meals near bedtime; and removing computers, electronic games, and mobile phones from bedrooms, he said.
Even sleep deprivation early in life may contribute. In the 1990s, the Avon Longitudinal Study of Parents and Children in the United Kingdom linked short sleep duration at 30 months with obesity at age 7, according to Dr. Taheri.
Although most of the data linking disrupted sleep patterns with obesity are cross-sectional and do not prove that the former causes the latter, sleep deprivation can contribute to physiologic changes that could lead to obesity.
For example, sleep deprivation can reduce levels of the hormone leptin, which signals an energy deficit, and increase levels of ghrelin, which may signal hunger, Dr. Taheri wrote. Fatigue stemming from sleep deprivation also can discourage physical activity, increasing the body's caloric surplus. And longer waking hours can increase opportunities to eat, also increasing the caloric surplus.
Despite this possible link, Dr. Taheri said it might be difficult to prove unequivocally a causal relationship between short sleep duration and obesity.