Cardiorespiratory fitness is positively associated with waist to height ratio and school socio economic status in irish primary school aged children

Background; The purpose of this paper is to examine any association between cardiorespiratory fitness (CRF) and markers of health among 6 and 10 year old Irish children. Methods; A total of 917 children (6 year olds, N=459; 10 year olds, N=458) from 11 primary schools in Cork (Ireland) participated. Body composition, blood pressure (BP), CRF (550-metre distance run) and school socio-economic status (SES) were assessed. Children were classified as low or high fitness based on run-time standard deviation scores (SDS). Physical activity (PA) determined over 1 week by accelerometry was collected from a sub sample of 700 children (76.3%). Results; Multiple linear regression revealed a positive association between run SDS and waist-to-height ratio (WHtR), (β=8.24, p\u3c0.0005) and SES (β=0.36, p=0.008) among 6 year olds. For 10 year olds WHtR (β=5.96, p=\u3c0.0005), SES (β=0.51, p\u3c0.0005), MVPA (β=-0.01, p=0.001) and resting heart rate (β=0.02, p\u3c0.0005) were positive predictors of run SDS. High fit 10 year olds had lower WHtR and body mass index and were less likely to be overweight or obese than their low fit counterparts. These children also spent less time sedentary and more time in light PA, vigorous PA and MVPA than low fit 10 year olds (p\u3c0.005). Discussion/Conclusions; Children with higher fitness had more favourable body composition. Efforts to improve the future health of Irish children should consider targeting the promotion of increased fitness and prioritise the distribution of resources to low SES schools