Cardiorespiratory Fitness Is Strongly Related to the Metabolic Syndrome in Adolescents

Abstract

The metabolic syndrome is a predecessor of type 2 diabetes and cardiovascular disease (1). In adults, physical activity is important for both preventing and treating metabolic syndrome (2). A limited number of studies have examined the impact of physical activity on metabolic syndrome in youth (3–7). The results from the few existing studies are conflicting, reporting no associations, weak effects, and strong effects of physical activity (3–7). These inconsistencies may reflect that most of these studies measured physical activity using self-report questionnaire measures, which have limited validity and reliability in youth (8,9). While one paper reported that the beneficial effects of physical activity on metabolic syndrome are limited to girls (3), published studies of physical activity and metabolic syndrome in youth have been limited to predominantly Caucasian samples and lack ethnic comparisons. Thus, it is unknown whether the effects of physical activity on metabolic syndrome are consistent in different population groups. The purpose of this study is to 1 ) examine the relation between objective measures of cardiorespiratory fitness (CRF) (the ability to perform endurance activities) and metabolic syndrome in adolescents and 2 ) determine whether the relationship is consistent by sex and ethnicity. The study sample consisted of 1,561 adolescents, aged 12–19 years, who participated in the National Health and Nutrition Examination Survey (NHANES) 1999–2002, which is a nationally representative cross-sectional survey (10 …