Recovery heart rate: an indicator of cardiovascular risk among middle school children

Recovery heart rate (RHR) has been used in adults to evaluate cardiovascular (CV) fitness, but less is known about RHR in children. Data from 1,276 participants in Project Healthy Schools, a school-based intervention in southeast Michigan, were collected. In addition, to demographic characteristics, physiologic factors examined included body mass index (BMI), lipid and glucose levels, blood pressure, and HR. Information on diet, physical activity, and sedentary behavior was collected through self-report. RHR was determined by measurement of HR after a 3-minute step test. Using quartiles of RHR as a marker of fitness, associations with demographic, physiologic, and behavioral factors were explored using χ(2) and Student t tests. Compared with children in the lowest quartile of RHR (i.e., most fit), those in the upper quartile of RHR (i.e., least fit) had greater mean LDL cholesterol (93.0 vs. 86.7 mg/dL; P = 0.02) and lower mean HDL cholesterol (50.9 vs. 55.9 mg/dL; P < 0.001). Children in the upper 95 % of BMI had greater mean RHR compared with those in the normal BMI range (116.6 vs. 100.3 kg/m(2)). Children in the upper quartile of RHR reported fewer days of vigorous to moderate exercise per week compared with children in the lowest quartile of RHR [4.8 vs. 4.1 (P < 0.001) for moderate exercise and 3.6 vs. 3.0 (P = 0.001) for vigorous exercise]. Among middle school children, RHR appears to be associated with physiologic parameters and health behaviors. RHR may be useful for identifying children at increased risk for developing CV risk factors.