'Few children get enough exercise'

Recommendations are for youngsters to take an hour a day of moderate to vigorous exercise but experts found that few were doing so.

They said it was "sobering" to think that activity peaks around the age of 11 and children take even less exercise as they go through adolescence.

Childhood obesity levels in the UK have been spiralling in recent years, with a fifth of boys and more than a fifth of girls expected to be obese by 2010.

Sir Derek Wanless said the Government's targets for cutting obesity had been "over-optimistic". The former NatWest bank chief used his report on progress in the NHS to warn that more needed to be done to tackle the growing problem.

The Health Survey for England, published last year, said 19% of boys and 22% of girls aged two to 15 will be obese by 2010. That would mean the Government misses its target to halt the year-on-year rise in childhood obesity.

The latest official figures show that, as of 2004, 19% of boys aged two to 15 are obese and 14% are overweight. Among girls the same age, 19% are obese and 17% are overweight. In 1995, the figures were far lower, with 11% of boys in that age group and 12% of girls being obese. Among girls and boys aged 11 to 15, the number who were obese almost doubled between 1995 and 2004.

The study, published ahead of print in the Archives of Disease in Childhood, involved studying more than 5,500 11-year-olds from the South West of England. It found boys took more exercise than girls, and they were also more likely to engage in moderate to vigorous forms of activity.

Just over a fifth (22%) of girls averaged at least one bout of moderate to vigorous activity a day, lasting at least five minutes. Among boys, this figure was almost double, at 40%. But both sexes spent most of their day doing activity considered to be of light intensity.

Fewer than 1% of the children averaged at least one 20-minute bout of exercise a day, while just 5% of boys and 2% of girls averaged at least one 10-minute bout. A total of 5.1% of the boys and 0.4% of the girls achieved the current recommended amount of physical activity, equating to 2.5% across both sexes. All the children were more active in the summer than in the winter.