NEW YORK: Not getting enough shut-eye each night may play a role in youngsters becoming overweight, partly by disrupting normal metabolism, a doctor from the University of Bristol, UK, contends in a report released on Thursday.

Although there is a “strong genetic contribution to obesity,” the current epidemic of obesity has been driven largely by environmental factors — an unhealthy diet and a lack of physical activity — Dr. Shahrad Taheri points out in the Archives of Disease in Childhood.

Moreover, there is an emerging body of research that suggests that sleep may impact energy balance and that short sleep duration may lead to metabolic changes that could help fuel the development of obesity, diabetes and cardiovascular disease.

Laboratory studies hint that as little as two to three nights of too little sleep in young adults can have profound negative effects on fat hormones.

In one study, for example, the hormone ghrelin, which is released by the stomach to signal hunger, was nearly 15 per cent higher in people sleeping only five hours per night versus the generally recommended eight hours. Inadequate sleep disturbs other hormones as well, including insulin, the stress hormone cortisol, and growth hormone, which could boost the desire for fatty foods.

Links between sleep deprivation and obesity seem to be particularly robust in children, Taheri notes, “in whom there is a linear dose-response relationship between shorter sleep and increased body weight.”

In general, children and adults are sleeping less today than in years past, Taheri also points out.—Reuters