New research from the UK is suggesting that parents vastly overestimate the amount of time their children spend exercising and the true levels are around six times lower than national data suggests.
The research says as a rule parents believe their offspring have more than two hours exercise a day, when in fact the actual figure is less than 30 minutes for both boys and girls.
The study by scientists at the Universities of Glasgow and Newcastle gives some indication of how little parents really know when it comes to what their children are doing in terms of exercise.
Government guidelines recommend exercise for at least an hour a day for children and were introduced in an attempt to curb the growing obesity problems in the young, attributed to unhealthy eating and sedentary lifestyles.
According to the body mass index (BMI) method of measurement, as many as one in three 11-year-olds in the UK is now considered to be overweight or obese.
But experts say for parents to work out how much exercise their child is doing is an impossible task and monitoring it is equally problematic.
The scientists fitted 130 six and seven-year-olds with an "accelerometer", a portable recording device worn on a waist belt, for one week, which measured exactly how how much time was spent on vigorous activities, such as brisk walking, running and sport.
The researchers then asked the children's parents how much exercise they thought that their children had done during the week using the Health Survey for England annual questionnaire.
The parents in turn provided an optimistic picture with 83% of boys and 56% of girls reportedly meeting the 60-minute guideline when in fact the accelerometer readings showed that in fact, only 3% of boys and 2% of girls had met the target.