Heart Rate Recovery, Central Systolic Pressure, and Augmentation Index in Young Healthy Individuals.

PURPOSE: Measuring heart rate recovery (HRR) holds valuable cardiovascular information and requires minimal technical skill and cost. Understanding the associations between HRR and more robust cardiovascular indicators, such as central systolic blood pressure (CSBP), can provide valuable cardiovascular information with less involvement. CSBP is a strong predictor of certain cardiovascular diseases. The study aims to examine the association between measures of HRR and CSBP and the augmentation index (AIx) in a group of young, healthy individuals and based on sex. PARTICIPANTS AND METHODS: One-hundred and seven participants (men - 55, women - 52) were measured for HRR at one minute (HRR1) and two minutes (HRR2) after maximum oxygen consumption (VO2max) testing, CSBP, and the AIx at a heart rate of 75 beats∙min-1 (AIx@75). RESULTS: The Pearson correlation indicated no association between HRR1, HRR2, and CSBP in men and women combined: r = 0.06, P = 0.53; r = 0.05, P = 0.59, respectively, or based on sex: men = r = 0.01, P = 0.95; r = 0.04, P = 0.79, respectively, and women = r = -0.05, P = 0.75; r = -0.09, P = 0.52, respectively. However, there were associations between HRR1 and AIx@75 in men and women combined: r = -0.37, P < 0.001, and based on sex: men = r = -0.31, P = 0.02, and women = r = -0.38, P < 0.01. CONCLUSION: Measures of HRR were not associated with CSBP in a combined group of young men and women or based on sex. Most measures of HRR, especially those established by parasympathetic nervous activity, were associated with lower AIx@75. Though measures of HRR might be good indicators of cardiovascular disease, they might not be good indicators of CSBP in young, healthy individuals.

Impaired autonomic function in normotensive obese children.

PURPOSE: To evaluate baroreflex sensitivity and autonomic control in a cohort of normotensive obese (OB) children. METHOD: A cross-sectional investigation, in which, baroreflex sensitivity and autonomic control were evaluated using transfer function and power spectral density analysis (PSDA) of the electrocardiogram and beat-to-beat blood pressures in normotensive OB children and normal weight normotensive controls. All methods used were noninvasive and data were captured while seated and at rest. RESULTS: The OB and control subjects non-obese (NO) were of similar age (OB 9.1±1.9 years vs. NO 9.2±1.4 years). The OB group was classified as having a BMI greater than the 95th percentile adjusted for age and gender, and a NO group with a BMI at or less than the 95th percentile (BMI percentile OB. 97.5±1.3 vs. NO 58.5±24.1). Both groups had similar normotensive blood pressures. T tests revealed that baroreflex sensitivity and HFRR were significantly reduced in the OB 9.2±2.7 vs. 15.2±4.7 (ms/mmHg) and 6.7±1.1 vs. 8.2±1.1 ms2, respectively, while LFSBP and LF/HF ratio were significantly increased in the OB 11.9±5.6 vs. 8.2±4.7 mmHg2 and 1.2±0.7 vs. 0.54±0.3, respectively. CONCLUSIONS: Normotensive OB children exhibited significantly reduced baroreflex sensitivity, parasympathetic control as well as increased sympathetic control when compared with healthy, NO controls. Findings in this investigation raise the awareness that autonomic dysfunction is present in young OB normotensive children.