ABC | Volume 112, Nº4, April 2019

Original Article Philbois et al Obesity and barorreflex sensitivity Arq Bras Cardiol. 2019; 112(4):424-429 Table 1 – Hemodynamic characteristics and values among healthy women and women with polycystic ovary syndrome (PCOS), subdivided into eutrophic PCOS (BMI < 25 kg/m 2 ) and obese PCOS (BMI > 30 kg/m 2 ) Control PCOS eutrophic PCOS obese p Ι p ΙΙ Characteristics Age, years 31.2 ± 6.6 28.5 ± 5.2 30.2 ± 5.3 0.053 0.107 Heights, meters 1.64 ± 5.0 1.62 ± 5.8 1.62 ± 7.9 0.102 0.649 Weight, kg 64 ± 10 60.6 ± 5.7 90.3 ± 10.9 *† 0.09 < 0.001 BMI, kg/m 2 23.5 ± 3 22.9 ± 1.6 33.9 ± 2.4 *† 0.494 < 0.001 Body fat percentage, % 25.6 ±3.6 26.4 ± 3.4 44.3 ± 3.3 *† 0.325 < 0.001 VO 2peak , L/min/kg 35.5 ± 3.3 31.9 ± 3.9 25.3 ± 3.3 *† 0.05 < 0.001 Hemodynamics Values HR (bpm) 76 ± 2.6 74.6 ± 2 77 ± 2 0.764 0.416 SBP (mmHg) 105 ± 8.9 101 ± 11.8 111 ± 9.5 † 0.057 < 0.001 DBP (mmHg) 70 ± 10.3 66 ± 9.6 76 ± 7.4 *† 0.05 < 0.001 MBP (mmHg) 84 ± 9 80 ± 9.8 90 ± 7.5 *† 0.05 < 0.001 Values expressed as means ± SD: standard deviation; m: Meters; Kg: kilogram; BMI: body mass index; VO 2peak : volume of oxygen consumed at the peak of exercise; L/min/Kg: liters per minutes per kilo; HR: heart rate; bpm: beat per minute; SBP: systolic blood pressure; DBP: diastolic blood pressure; MBP: mean blood pressure; mmHg: millimeters of mercury; statistical difference when p < 0.05; (*) vs. Control; (†) vs. eutrophic PCOS; P Ι : eutrophic control group vs PCOS eutrophic group; P ΙΙ : PCOS eutrophic group vs. PCOS obese group. Results The volunteer’s anthropometric characteristics and hemodynamic parameters are in Table 1. The obese PCOS group had higher BMI, weight and body fat percentage than the other groups. On the other hand, VO 2peak was lower in the obese PCOS group. In relation to blood pressure, the obese group had higher values of diastolic blood pressure and mean blood pressure compared to the control and eutrophic PCOS groups. Table 2 presents the spectral analysis of HRV and BPV results during rest of all groups studied. The HRV analysis at rest shows the obese PCOS group had lower variance. In addition, the control groups and eutrophic PCOS presented higher LF and HF oscillations in absolute values than the obese PCOS group. There were no differences between the groups in BPV analysis. The results of BRS analysis obtained during rest in all groups studied, control, eutrophic PCOS and obese PCOS, are seen in Table 3, that show at rest the obese PCOS group presented lower spontaneous BRS than the others groups. In addition, it is important to note that the control group demonstrated a higher baroreflex effectiveness index. Discussion The present study mainly findings were, at rest the obese PCOS group had lower HRV and BRS than the other two groups, BPV was similar across groups. Regarding hemodynamic values, PCOS obese group showed the highest values of systolic, diastolic and mean blood pressure compared to other groups, despite the fact that all subjects were normotensive; some studies had also show a relation with body fat increase and increase BP values. 9,10,21,22 To VO 2peak , the obese PCOS group had the lowest value, similarity to literature, which some authors found a negative correlation between obesity and VO2peak. 21,22 There are few studies in the literature about obesity and PCOS, which are contradictory, some point to this association as a negative factor in HRV, 3,4 although others report that there is no association between weight gain and PCOS. 11,23 In this sense, the lower HRV found in the obese PCOS group in the present study suggests that this change is due to obesity. The literature indicates that the obesity mechanisms may be associated with a reduced sympathetic system response in the postsynaptic region since they had found in presynaptic cleft a high sympathetic activity represented by high concentration of noradrenaline. 24,25 In addition, a recent study carried out in our laboratory showed low frequency (LF) and high frequency (HF) bands differences, in absolute and normalized units, in healthy and sedentary women with normal BMI, overweight and obesity, they verified that the obese group had lower LF and HF oscillations. 10 Regarding BRS, the eutrophic PCOS and control groups presented similar values, agreeing with Lambert, 2015, in which the groups had similar BMI and BRS values. In relation to the obese PCOS group, it had the lowest values in all BRS parameters than the others two eutrophic groups, suggesting that obesity may be responsible for a reduction in BRS. In this sense, a study comparing BRS in women divided by BMI indicates a BRS reduction with gain weight, observed by the BRS gain value, in this way, the BRS decrease might correlate to weight increase. 26 However, it is known that BRS is also influenced by many other factors like insulin resistance, blood glucose, sodium sensibility, genetic markers and ovarian hormones. 27,28 In the present study, neither of these other factors were measuring. Thereby it is possible to suggest that obesity may influenced in BRS values, as observed in another study, 26 although further studies are needed to confirm these findings in PCOS women. 426