Based on one of the methods23 78% of the children met the recommendation of at least one hour per day spent in moderate to vigorous physical activity. Based on the other method24 this was only the case for 3% of the children. Thus, the methodology to estimate the amount and the intensity of physical activity in children is challenged. Recommendations for physical activity for children below 5 years of age have been established by The Danish Health Authority, however, due to lack of research examining this agegroup, they do not include recommendations regarding neither the intensity of activity nor the duration of the activity. A recent study of 3- to 4-year-olds25 showed that all children in this age group accumulated at least 180 minutes of physical activity per day. An amount of 180 minutes physical activity per day is equivalent to the Canadian guidelines for physical activity in this age group26. However, having the methodological problems of interpreting objective measures of physical activity in mind, it is premature to conclude that all children below the age of 5 accumulate enough physical activity. To have a clear estimate of physical activity in children and youth demands a better and standardized way to analyze and interpret data from objective as well as subjective measurement tools.
Research gaps • There is a profound need for standardizing the methods for assessing the proportion of children meeting the physical activity guidelines for physical activity including standardization of how the recommendation is operationalized. • The choice of methods to analyze and interpret objective physical activity data might influence the identified percentage of children complying with the recommendations for physical activity21. Furthermore, questionnaires to measure physical activity in children have to ask the same questions in the same context to be comparable over time. Thus, more research is needed to validate physical activity measures. • Objective data on physical activity that are nationally representative, with sampling in all 5 regions in Denmark, are needed.
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