Children who do not sleep well at night are more likely to become overweight, according to researchers from New Zealand.

A research published in the on-line edition of the magazine "VMJ", followed 244 children between 3 and 7 years. The result was that more sleep is associated with lower weight, which could have significant implications on public health.

The children were examined every 6 months and measured their weight, height and body fat. The sleep habits and physical activity levels were recorded at ages 3, 4 and 5 years.

The researchers found that children who slept less during the first years of their life are at greater risk to have a higher BMI (Body Mass Index) at the age 7 years.

The association remained even when other risk factors such as gender and physical activity were taken into account. This indicates the relationship between food and hormonal changes that affect appetite.

To a complementary analysis professors Francesco Cappuccio and Michelle Miller from Warwick university, stated that further investigation will have to take place to find the behavioural methods that will not be  depended on medicines for extending the sleep duration both of children and adults.

Meanwhile, they note, that it would not hurt to advise people that the regular reduction of hours of sleep can contribute to long-term ill-health. Dr Ian Maconochie, of Royal College of Paediatrics and Child Health, stated that children below of 5 years old in general sleep around 11 hours.

They added, however, that 20% of this age have trouble sleeping and already know that poor sleep has a significant effect on attention, memory and school performance. The investigation, they believe, is useful information on knowledge relating to sleep habits of children.