British researchers have found that even children at kinder garden can find school a stressful place.
The researchers from Bath University say they have found the presence of the stress hormone cortisol in children younger than five.
The researchers suggest it may well be that parents who are themselves stressed about their children starting school are passing their anxieties onto their children.
Children in Britain start school at five and as in many other countries begin in a reception or kinder garden class.
The researchers began collecting data on 105 children three to six months before they started school and found instead of providing a baseline, the results showed that cortisol levels were already high three to six months before school started.
For the study parents were asked to complete questionnaires about their child's behaviour and personality and small samples of the children's' saliva were collected three to six months before children joined the class, and again about two weeks into the first term and then again six months after.
The samples were then analysed for cortisol levels which tend to rise when the body is under stress in order to assess how anxious children were about events.
The team found levels of cortisol peaked in the samples taken at the start of term, but that they were also above the normal range in the samples taken three to six months before school started.
They had however returned to the normal range six months after school had started.