1 Obesity Research, Department of Nutrition, Exercise and Sports, Faculty of Science, Københavns Universitet2 Department of Nutrition, Exercise and Sports, Department of Nutrition, Exercise and Sports, Faculty of Science, Københavns Universitet3 Copenhagen University Hospital4 Prevention and Treatment of Obesity and Appetite and Energy Metabolism, Department of Human Nutrition, Faculty of Life Sciences, Københavns Universitet5 Prevention and Treatment of Obesity and Appetite and Energy Metabolism, Department of Human Nutrition, Faculty of Life Sciences, Københavns Universitet6 Department of Nutrition, Exercise and Sports, Department of Nutrition, Exercise and Sports, Faculty of Science, Københavns Universitet
Purpose: To evaluate the effects of weight loss on heart rate (HR) and heart rate variability (HRV) parameters in overweight postmenopausal women. Design and Methods: Forty-nine overweight postmenopausal women with an average body mass index of 28.8 1.9 kg/m2 underwent a 12-week dietary weight-loss programme. Accepted variables for characterization of HRV were analysed before and after the weight loss by 24-h ambulatory ECG monitoring; mean and standard deviation for the time between normal-to-normal complexes (MeanNN and SDNN, respectively), and the mean of standard deviations of normal-to-normal intervals for each 5-min period (SDNNindex). Baseline body fat mass (FM%) and changes in body composition was determined by dual X-ray absorptiometry. Before and after the weight-loss period, total abdominal fat, intra-abdominal fat (IAAT), and subcutaneous abdominal fat (SCAT) were measured by single-slice MRI at L3. Results: The weight loss of 3.9 2.0 kg was accompanied by an improvement of HRV. SDNN increased by 9.2% (p ¼ 0.003) and SDNNindex increased by 11.4% (p ¼ 0.0003). MeanNN increased by 2.4%, reflecting a decrease in mean heart rate from 74.1 to 72.3 beats/min (p ¼ 0.033). Systolic blood pressure (SBP) decreased by 2.7%, total cholesterol by 5.1% and high-sensitivity C-reactive protein (hsCRP) by 15.8% (p ¼ 0.002). Improvements in SDNN and cholesterol were correlated with weight loss (r ¼ 0.329, p ¼ 0.024 and r ¼ 0.327, p ¼ 0.020, respectively) but changes in HR, SBP, and hsCRP were not. IAAT and the IAAT/SCAT-ratio were found to be negatively associated with HRV parameters but changes in body composition were not associated with changes in HRV. Conclusions: The observed improvement of HRV seems to be facilitated by weight loss. IAAT and the IAAT/SCAT ratio were found to be associated with low HRV.
European Journal of Preventive Cardiology, 2013, Vol 20, Issue 4, p. 671-677