These findings suggest that AST should be promoted to increase PA levels in children and adolescents and that cycling to/ from school is associated with increased cardiovascular fitness .
BACKGROUND The impact of  active school transport ( AST )  on daily physical activity ( PA ) levels , body composition and cardiovascular fitness remains unclear .
Physical activity and clustered cardiovascular risk in children: a cross-sectional study (The European Youth Heart Study)
BACKGROUND Atherosclerosis develops from early childhood ; physical activity could positively affect this process . This study 's aim was to assess the associations of objective ly measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis . METHODS We did a cross-sectional study of 1732 r and omly selected 9-year-old and 15-year-old school children from Denmark , Estonia , and Portugal . Risk factors included in the composite risk factor score ( mean of Z scores ) were systolic blood pressure , triglyceride , total cholesterol/HDL ratio , insulin resistance , sum of four skinfolds , and aerobic fitness . Individuals with a risk score above 1 SD of the composite variable were defined as being at risk . Physical activity was assessed by accelerometry . FINDINGS Odds ratios for having clustered risk for ascending quintiles of  physical activity  ( counts per min ; cpm ) were 3.29 ( 95 % CI 1.96 - 5.52 ) , 3.13 ( 1.87 - 5.25 ) , 2.51 ( 1.47 - 4.26 ) , and 2.03 ( 1.18 - 3.50 ) , respectively , compared with the most active quintile . The first to the third quintile of physical activity had a raised risk in all analyses . The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children . INTERPRETATION  Physical activity  levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors
These findings suggest that AST should be promoted to increase PA levels in children and adolescents and that cycling to/ from school is associated with increased cardiovascular fitness .
BACKGROUND The impact of  active school transport ( AST )  on daily physical activity ( PA ) levels , body composition and cardiovascular fitness remains unclear .