Cardiovascular and Metabolic Effects of Exercise Training in High‐fat Diet‐fed Ovariectomized Mice: Comparison Between Moderate Intensity Continuous vs. High Intensity Interval Training

Despite the consensus on the benefits of moderate intensity continuous exercise for the treatment of cardiometabolic risk factors after menopause, little is known about the effects of high intensity interval training. Thus, the objective of this study was to compare the metabolic and cardiovascular effects between moderate intensity exercise training (60% of maximum exercise capacity) vs. high intensity interval training (HIIT) (90% of maximum exercise capacity, interspersed with 25% of the maximum capacity) in high‐fat diet (HF‐diet) ovariectomized mice. Twenty C57BL/6J ovariectomized mice were divided into: control (OvxC) and submitted to HF‐diet (OvxHF), HF‐diet submitted to moderate‐intensity exercise training (OvxHFT60) or submitted to HIIT (OvxHFT90). The animals were fed HF‐diet for 9 weeks, ovariectomy (bilateral surgical removal of ovaries) was performed at 5 th week, and exercise training was performed from 6 th to 9 th weeks (4 weeks; 5 days at week; ~1hour/day). At the end of 9 weeks, blood glucose evaluations and oral glucose tolerance test were performed. Arterial pressure (AP) was assessed by direct recording (4kHz, CODAS) after 24h of carotid artery cannulation. Baroreflex sensitivity was tested by injections of phenylephrine and sodium nitroprusside. The AP records were used for analysis of cardiovascular autonomic modulation in time and frequency domains. The HF‐diet induced increase in body weight, in blood glucose, reduction in glucose tolerance, increase in mean AP (OvxC: 118±1.7; OvxHF: 123±2.1; OvxHFT60: 120±1.4; OvxHFT90: 118±2.8 mmHg) and in cardiac sympathetic modulation (LF‐PI: OvxC: 0.29±0.02; OvxHF: 0.55±0.02; OvxHFT60: 0.13±0.02; OvxHFT90: 0.33±0.09 ms 2 ). The moderate intensity exercise training not avoid the increase in body weight, but avoid the increase in mean AP and promotes resting bradycardia, associated to baroreflex sensitivity improvement, greater cardiac parasympathetic modulation (HF‐PI: OvxC: 0.67±0.02; OvxHF: 0.47±0.04; OvxHFT60: 0.86±0.02; OvxHFT90: 0.65±0.09 ms 2 ), and lower cardiac and vascular sympathetic modulation. The high intensity interval training promotes reduction in body weight, blood glucose (OvxC: 95±4; OvxHF: 107±2; OvxHFT60: 162±1; OvxHFT90: 134±6 mg/dL), increase in glucose tolerance, and avoid the increase in mean AP associated to baroreflex sensitivity improvements for tachycardic responses (OvxC: 4.1±1.4; OvxHF: 2.7±0.6; OvxHFT60: 8.8±0.5; OvxHF90: 7.2±0.9 bpm/mmHg). In conclusion, the high intensity interval training was more effective in promoting metabolic benefits; however, moderate intensity continuous exercise training was more effective in promoting cardiovascular benefits. Support or Funding Information CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .