Objective: The purpose of this study was to investigate the heart rate variability (HRV) profile in obese women displaying the metabolically healthy but obese (MHO) phenotype.
Design: We studied 47 obese, sedentary postmenopausal women. Subjects were classified as MHO or at risk based on insulin resistance as assessed with the homeostatic model assessment (HOMA) index. Subjects were divided into tertiles according to HOMA values. Subjects in the lower tertile were categorised as MHO while subjects in the upper 2 tertiles represented at risk subjects. Outcome measures were heart rate variability factors (RR intervals, SDNN, LF, HF, pNN50, RMSSD), body temperature, body composition (DEXA) and a lipid profile as well as glucose and insulin.
Results: MHO individuals had significantly lower resting heart rate, body temperature, lean body mass as well as fasting insulin and HOMA levels compared to at risk subjects (p < 0.05). In addition, RR intervals, SDNN and LF were significantly higher in MHO individuals (p < 0.05). Moreover, stepwise regression analysis showed that SDNN was an independent predictor of the variation in HOMA in our cohort.
Conclusion: Results of the present study indicate that postmenopausal women displaying the MHO phenotype present a favourable HRV profile. Therefore, higher HRV could be associated, at least in part, in the protective profile of MHO individuals.