A trend for children and adolescents to stay up late and sleep less may be linked to rising levels of obesity, according to a review of existing research published on Thursday.
Bristol University researcher Shahad Taheri said televisions, computers, mobile phones and other gadgets should be banned from children's bedrooms to enable them to get a good night's sleep.
Writing in the journal Archives of Disease in Childhood,Taheri said there was increasing evidence that shortened sleeping times result in metabolic changes that may contribute to obesity, diabetes and heart disease.
A UK study published last year indicated that insufficient sleep in infants aged 30 months was associated with obesity by the time they reached the age of seven. Taheri said this suggested that sleep loss at a young age may alter the body's mechanisms that regulate appetite and energy expenditure.
Limited sleep is also a problem for teenagers, whose need for sleep increases during the critical years of adolescent development. Other research, published by Taheri in 2004, found that adults sleeping only five hours had almost 15 per cent higher levels of ghrelin — a hormone released by the stomach to signal hunger — than those managing eight hours.
Children waking up tired from not enough sleep were also likely to take less physical exercise, adding to the likelihood of putting on weight, Taheri said.