Children need to exercise for longer than the recommended one hour each day, according to researchers.
The team from the University of Zaragoza, Spain, believe kids who follow the current guidelines are still at risk of heart and blood circulation problems in the future.
The researchers said children who have not yet celebrated their 10th birthday should exercise for at least 80 minutes every day, including 20 minutes at a higher intensity.
They became the first to explore the link between physical activity as a child and the risk of developing cardiovascular disease (CVD).
The risks of CVD were determined by studying factors like blood pressure, cholesterol levels and skin folding in 3,000 children between the ages of two and nine.
The study team found 15% of the participants had an increased risk of CVD, while children who had not even turned six yet were considered unhealthy.
The researchers have suggested wide-ranging guidelines as risk differs depending on age and gender. They have recommended over 70 minutes of moderate-to-vigorous physical activity for boys under the age of six, with older boys needing more than 80 minutes. Girls need around an hour, regardless of how old they are.
The findings, published in the journal BMC Medicine, appear to show guidelines that recommend children get around an hour of moderate-to-vigorous exercise each day are not improving health, with some kids who follow them still having unhealthy CVD profiles.
Copyright Press Association 2013