Pupils who lack sleep gain the worst academic results, according to a recent US study. The research, carried out by the University of Massachusetts and published in the journal Child Development, also found that pupils aged 11 to 13 are suffering from depression and low self-esteem because of lack of rest.
Girls found it harder to get enough sleep, possibly because they entered puberty earlier, creating a greater need for it.
There is a large body of education research that says students perform better with more sleep. It is accepted that teenagers need at least nine hours of sleep a night, compared with eight for adults.
Some schools in the US have been experimenting with opening an hour later in the morning to give their students that extra hour's sleep - and avoid them sleeping through early morning classes.
Minneapolis public schools took this measure after the University of Minnesota released a study showing that later start times improved student participation.
The schools have been pleased with the results - follow-up surveys showed that students were actually sleeping an extra hour, not just going to bed an hour later as critics had predicted. And with students more alert, teachers felt they could do a better job. Attendance also increased.
Younger pupils' mental health risk
Researchers in Britain have suggested that teachers should make greater allowances for young children after it was found that the youngest pupils in a class are at an increased risk of mental health problems.
Writing in the British Medical Journal, the researchers said the risks applied to students in primary and secondary school and maybe even at university.
Professor Robert Goodman and colleagues at the Institute of Psychiatry in London surveyed 9,383 five to 15-year-olds in England and Wales.
They found that children in the youngest third of a class had a much higher rate of psychiatric disorder, which included anxiety, depression, behavioural and emotional difficulties.
The researchers said these risks could be reduced if teachers and schools made greater allowances for the youngest class members.
"Several studies suggest that teachers often forget to make allowances for relative age, expecting too much of the younger children and being more likely to see them as failing." They said teachers could remind themselves that not all children are at the same stage by taking steps like calling the register in birth order rather than alphabetically and grouping children together by age.
In addition, steps could be taken to reduce the stress on young children, they said.
"Streaming children according to their relative age within each year group may also be helpful, as may allowing children to repeat a year," they wrote.
Education best route to stronger economy
Adequate and effective funding of education is the best way to achieve faster growth, more jobs, greater productivity and more widely shared prosperity, according to a report by the Economic Policy Institute in the US.
The report uses a compelling body of research to show how increased investment in all levels of education, from pre-school to university, helps economic development through increases in productivity, learned skills, technology and workers' average earnings.
At a time when the knowledge-based economy demands increasingly higher skills to stay competitive, support for well-resourced schooling and training is key, the report says.
"If our goal is an economic climate that provides good jobs, decent living standards, entrepreneurial workers and a competitive edge over other countries, then investing in education is the single most important thing we can do. Education should be thought of in terms of productivity, innovation, and the growing of wealth."
The report examines nearly 180 studies that show the relationship between education investment and quality and economic development, emphasising, for example, how schools provide not just greater knowledge but also an improvement of the lives of current and future workers.
One of the report's major findings is that those with less than a high school diploma saw their mean family income decline by 14 per cent between 1979 and 1995, but college graduates' mean income rose by 14 per cent.