A study based on over 11,000 children from UK has found that children who go to bed late have poor brain development and subsequently have lower scores in tests.
Preschoolers and school-going children need to sleep for about 10-11 hours every night. School-work along with extracurricular activities and sports requires tremendous amounts of energy and with the increase in exposure to media such as TV and internet, children often get inadequate sleep. Caffeine intake and watching disturbing content on TV could lead to disturbed sleep. Children who don't get enough sleep at night tend to develop behavioral problems, mood swings and cognitive problems.
The present study looked at the effects of late or irregular bedtimes on 11,000 seven year old children.
The data for the study came from U.K. Millennium Cohort Study (MCS), which has tracked UK children born between September 2000 and January 2002.
Researchers found that children who went to bed after 9pm every night, hailed from an economically disadvantaged group. Most of seven year olds who had irregular bedtimes or slept after 9 pm had lower scores in tests that assess brain development of the child. The association between late bedtimes and poor scores was strongest among seven-year-old girls than boys.
"Sleep is the price we pay for plasticity on the prior day and the investment needed to allow learning fresh the next day. Early child development has profound influences on health and wellbeing across the life course. Therefore, reduced or disrupted sleep, especially if it occurs at key times in development, could have important impacts on health throughout life," the authors wrote.
The study also found that irregular or late bedtimes at age 3 were associated with poor scores in reading, math, and spatial awareness in both boys and girls.
Girls who had irregular bedtimes at 3,5 and 7 years of age performed badly at cognitive tests than their peers with regular bedtimes.
"At first glance, this research might seem to suggest that less sleep makes children less intelligent, however, it is clearly more complicated than that," Dr Robert Scott-Jupp of the Royal College of Paediatrics and Child Health told BBC News. "While it's likely that social and biological brain development factors are inter-related in a complex way, in my opinion, for schoolchildren to perform their best, they should all, whatever their background, get a good night's sleep."
The study is published in the Journal of Epidemiology and Community Health.