Inverse correlation between heart rate recovery and metabolic risks in healthy children and adolescents

OBJECTIVE - Heart rate recovery (HRR) is a marker for survival. Little is known about the association between HRR and metabolic risks in healthy children or adolescents. RESEARCH DESIGN AND METHODS - We examined 993 healthy children and adolescents aged 12-19 years with reliable measures of cardiovascular fitness from the National Health and Nutrition Examination Survey 1999-2002. HRR parameters 1-3 min after exercise were calculated from exercise test results. Anthropometric and metabolic risk factors as well as metabolic Z score were obtained. RESULTS - The HRR parameters were inversely correlated with most of the metabolic risks, including waist circumference, systolic blood pressure (SBP), serum triglycerides, and serum C-reactive protein (CRP) levels, and were positively correlated with serum HDL levels. In multiple linear regression analysis, among the metabolic risks, waist circumference was the only parameter associated with HRR parameters (P = 0.038, 0.001, and 0.001 for 1-, 2-, and 3-min HRR, respectively) in boys. In girls, waist circumference (P = 0.001 and < 0.001 for 2- and 3-min HRR, respectively), SBP (P = 0.029 for 1-min HRR), serum glucose (P = 0.021 for 2-min HRR), and serum CRP (P = 0.007 for 2-min HRR) levels were the most important determinants of HRR parameters. The adjusted 1-min HRR did not change across four quartiles of metabolic Z score, while the adjusted 3-min HRR decreased significantly with four quartiles of metabolic Z score. CONCLUSIONS - Metabolic risks are inversely associated with HRR in healthy children and adolescents. Our finding suggests that there is a link between metabolic risks and autonomic nervous system functions in healthy young ages. ? 2008 by the American Diabetes Association.