Different Volumes of Exercise Training in an Experimental Model of Menopause and Obesity: Metabolic, Hemodynamic and Autonomic Effects

Abstract

After menopause there is a greater tendency to visceral fat accumulation and increased arterial pressure, contributing to obesity and increased cardiovascular risk. On the other hand, exercise training promotes important benefits on cardiometabolic risk factors. In this sense, the American College of Sports Medicine suggests that the weekly frequency to practice regular physical activity should be, at least, 3 days a week. However, this recommendation applies to the general population, so the association of risk factors that is so frequently observed after menopause is not considered. Thus, the aim of this study was to compare the effects of different volumes of moderate aerobic exercise training on metabolic, hemodynamic and autonomic parameters in an experimental model of menopause fed with high‐fat diet. For this, 32 C57BL/6J ovariectomized mice fed a high‐fat diet were used, divided into 4 groups (n=8 each): sedentary (OSD); trained 3 days a week (OTD3); trained 5 days a week (OTD5); trained 7 days a week (OTD7). The administration of the high‐fat diet lasted 9 weeks, and the ovariectomy was performed at the end of the 4th week. Fasting glycemia and oral glucose tolerance were assessed before the ovariectomy and at the end of the study. Exercise training lasted 4 weeks (6th to 9th week of the protocol) at moderate intensity. At the end of the study, the animals were cannulated for direct arterial pressure recording, baroreflex sensitivity and cardiovascular autonomic modulation analysis. The results demonstrate that the greater volume of exercise training (OTD7) provided a marked reduction in body weight, adipose tissue (OSD: 0.060±0.007; OTD3: 0.051±0.005; OTD5: 0.052±0.009; OTD7: 0.029±0.003 grams) and blood glucose fasting time (OSD: 158±6; OTD3: 145±5; OTD5: 143±5; OTD7: 133±5 mg/dL). In cardiovascular parameters, both exercise training performed 5 days (OTD5) and 7 days (OTD7) a week were able to reduce systolic and mean arterial pressure (OSD: 113±2; OTD3: 111±2; OTD5: 102±3; OTD7: 103±2 mmHg), heart rate (OSD: 655±14; OTD3: 538±30; OTD5: 532±36; OTD7: 520±12 bpm), improve baroreflex sensitivity (Bradycardic response ‐ OSD: 1.5±0.2; OTD3: 2.1±0.1; OTD5: 2.5±0.3; OTD7: 2.4±0.1 bpm/mmHg), increase parasympathetic modulation (AF‐IP ‐ OSD: 16.5±1.8; OTD3: 20.8±2.2; OTD5: 39.1±7.5; OTD7: 38.8±8.4 nu), reduce sympathovagal balance (LF/HF ‐ OSD: 2,7±0.6; OTD3: 1.7±0.2; OTD5: 0.9±0.3; OTD7: 0.9±0.2) and improve the variance of systolic arterial pressure (VAR‐SAP ‐ OSD: 20±4; OTD3: 19±2; OTD5: 10±2; OTD7: 11±2 mg/dL). In conclusion, the female public, especially after menopause, lacks specific guidelines for the practice of physical activity, since the minimum recommended for the general population (3 days a week) is not effective in managing the observed cardiometabolic risk factors in the association of ovarian deprivation and obesity. Support or Funding Information This study was supported by CNPq (435123/2018‐1 ICS).