New Scientist Television watching may hasten puberty
Children who watch a lot of television produce less melatonin, new research suggests - the "sleep hormone" has been linked to timing of puberty.
Scientists at the University of Florence in Italy found that when youngsters were deprived of their TV sets, computers and video games, their melatonin production increased by an average 30 per cent.
“Girls are reaching puberty much earlier than in the 1950s. One reason is due to their average increase in weight; but another may be due to reduced levels of melatonin,” suggests Roberto Salti, who led the study. “Animal studies have shown that low melatonin levels have an important role in promoting an early onset of puberty.”
Salti and colleagues studied 74 children aged between six and 12 years old, who normally watched an average three hours of television in the evening between 2000 and midnight. The youngsters, from the Tuscan town of Cavriglia, were encouraged to watch more TV than usual for a week preceding the study.
During the subsequent seven-day experiment, the children were not allowed to watch TV and their families were also asked to reduce the use of other sources of artificial light. At the end of the week, the children’s melatonin levels had risen by an average of 30 per cent, and the effect was most pronounced in the youngest children.
The mechanism behind melatonin production is poorly understood. But it is thought that prolonged exposure to artificial light reduces the body’s production of melatonin, whereas experiencing regular intervals of natural sunlight and darkness increases it.
Commenting on the research, Alessandra Graziottin, director of the Centre for Gynaecology and Medical Sexology in Milan, said the results were very interesting and plausible. She told La Repubblica newspaper: “US studies have shown that the greater the exposure to television, the earlier the age of sexual experience, including teenage pregnancies.”
Other studies have shown that children who spend a lot of time watching television or playing video games weigh more than other children, which might also exacerbate the early onset of puberty.
Children who watch a lot of television produce less melatonin, new research suggests - the "sleep hormone" has been linked to timing of puberty.
Scientists at the University of Florence in Italy found that when youngsters were deprived of their TV sets, computers and video games, their melatonin production increased by an average 30 per cent.
“Girls are reaching puberty much earlier than in the 1950s. One reason is due to their average increase in weight; but another may be due to reduced levels of melatonin,” suggests Roberto Salti, who led the study. “Animal studies have shown that low melatonin levels have an important role in promoting an early onset of puberty.”
Salti and colleagues studied 74 children aged between six and 12 years old, who normally watched an average three hours of television in the evening between 2000 and midnight. The youngsters, from the Tuscan town of Cavriglia, were encouraged to watch more TV than usual for a week preceding the study.
During the subsequent seven-day experiment, the children were not allowed to watch TV and their families were also asked to reduce the use of other sources of artificial light. At the end of the week, the children’s melatonin levels had risen by an average of 30 per cent, and the effect was most pronounced in the youngest children.
The mechanism behind melatonin production is poorly understood. But it is thought that prolonged exposure to artificial light reduces the body’s production of melatonin, whereas experiencing regular intervals of natural sunlight and darkness increases it.
Commenting on the research, Alessandra Graziottin, director of the Centre for Gynaecology and Medical Sexology in Milan, said the results were very interesting and plausible. She told La Repubblica newspaper: “US studies have shown that the greater the exposure to television, the earlier the age of sexual experience, including teenage pregnancies.”
Other studies have shown that children who spend a lot of time watching television or playing video games weigh more than other children, which might also exacerbate the early onset of puberty.
Comments