This study aimed to derive guidelines on physical activity. We did a cross-sectional study of 1732 9-year-old and 15-year-old children. Objectively measured physical activity was associated to clustered CVD risk with an OR for the least active of 3.29 compared with the most active quintile. The time spent in moderate activity in children where risk was elevated was less than 116 min per day in 9-year-old and less than 88 min per day in 15-year-old children. Physical activity levels should be higher than the current international guidelines of at least 1 h per day to prevent clustering of CVD risk factors.