Physical abilities and academic performance : cross-sectional and longitudinal studies of Icelandic children

Abstract

Background: The academic performance of children has been correlated with their future educational attainment and health and has therefore been viewed as a public health concern. Physical activity and cardiorespiratory fitness are known to exert many beneficial effects on the physical and mental health of children, but the relationship with academic performance remains unclear. The relationship between adiposity and academic performance also remains inconclusive. Aim: The main aim of this dissertation was to examine the associations between cardiorespiratory fitness, physical activity, adiposity and academic performance using cross-sectional and longitudinal data. Methods: This dissertation builds on data from three different studies. The first was a cross-sectional study conducted in 2003 titled Lifestyles of 9- and 15-year-old Icelanders, n = 448 subjects. The second study was a two-year cluster randomized intervention trial conducted between 2006 and 2008 on 7-year-old school children titled Lifestyles of 7 – 9-year-old children: intervention towards better health, n = 267 subjects. The third study was a follow up of the second study titled Longitudinal study of physical health status in a young Icelandic cohort (born in 1999): Interrelations with sleep and educational attainment, n = 321 subjects. Physical activity was measured by accelerometers and by a self-report instrument. Cardiorespiratory fitness was assessed by a cycle ergometer, and adiposity was determined by calculating the body mass index (BMI) and body fat percentage via a Dual Energy X-ray Absorptiometry (DXA) scan. The results from standardized testing retrieved from the Directorate of Education were used to assess academic performance. Results: No cross-sectional or longitudinal associations were identified between physical activity, cardiorespiratory fitness, and academic performance. Self-reported physical activity (frequency of sport participation) was associated with higher math performance in 9-year-olds. A long-term increase in adiposity level was associated with deteriorating academic performance in math, independent of changes in physical activity. Conclusions: An increase in adiposity from the fourth to 10th grades was accompanied by worsening academic performance. Further studies are required to identify factors that may negatively affect both changes in academics and body composition in school-aged children.

Bakgrunnur: Sýnt hefur verið fram á að regluleg hreyfing, og í framhaldi þrek, hefur góð áhrif á heilsufar ungs fólks. Tengsl milli hreyfingar og námsgetu hafa verið rannsökuð en niðurstaðan er óljós. Það sama gildir um tengsl milli líkamsfitu og námsárangurs. Markmið: Að skoða tengsl hreyfingar, þreks og líkamsfitu við námsárangur hjá íslenskum börnum og unglingum. Aðferð: Stuðst var við gagnasöfn frá þremur íslenskum rannsóknum á lífsstíl og heilsufari þátttakenda. Þverskurðartengsl sem og langtímatengsl voru rannsökuð. Hreyfing var mæld með hreyfimælum en einnig sögðu þátttakendur sjálfir frá hve mikið þeir hreyfðu sig. Þrek var mælt með stigvaxandi hámarksprófi á þrekhjóli og líkamsfita var metin með líkamsþyngdarstuðli og hlutfalli líkamsfitu af heildar þyngd (DXA mæling). Niðurstöður úr samræmdum prófum voru notaðar til að meta námsárangur. Niðurstöður: Hvorki hreyfing né þrek reyndust hafa tengsl við námsárangur, hvorki í þverskurðarsniðið né langtímasniði. Þeir nemendur sem voru í offituflokki reyndust hafa lægri einkunnir en aðrir nemendur og aukning á líkamsfitu umfram meðaltal frá 9 -15 ára aldri tengdist lakari námsgetu. Ályktun: Aukning á líkamsfitu er áhættuþáttur gagnvart námsgetu barna og unglinga. Erfitt er að segja til um orsakasamhengi en frekari rannsókna er þörf á þáttum sem geta tengst báðum þáttum. Heildarhreyfing, mæld með hreyfimælum virðist ekki vera tengd námsgetu en við frekari flokkun á hreyfingu geta komið fram tengsli s.b.r. fjöldi íþróttaæfinga í viku.