ABC | Volume 115, Nº2, August 2020

Original Article Basilio et al. Effects of intermittent fasting on the heart Arq Bras Cardiol. 2020; 115(2):184-193 group. Buthani et al., 32 in a study on humans, showed that trained volunteers, even with increased hunger, did not exhibit a significant increase in food intake. According to our initial hypothesis, exercise training on a treadmill attenuates metabolic disorders and cardiac remodeling induced by intermittent fasting. In addition to reducing energy efficiency, intermittent fasting modified glucose tolerance, which may be associated with better insulin sensitivity. The fact that insulin promotes lipogenic effects in the adipose tissue 33 may explain why the groups undergoing intermittent fasting did not show significant differences in body adiposity compared to the respective controls (Table 2). Insulin release increases in the presence of greater nutrient availability, such as during the postprandial period. Improvement in insulin sensitivity by adopting an intermittent fasting regime was also found in a recent study on mice. 34 On the other hand, the combination of intermittent fasting and exercise training reduced body adiposity in the ETI group. Exercise training promotes cardiorespiratory, neural and hormonal adaptations and adjustments. 9,15,16 Within the endocrine context, hormone secretion is also altered by exercise. In the study by Evans et al., 35 aerobic exercise for 12 months improved insulin sensitivity, with a 19.4% decrease in the area under the oral glucose tolerance curve in older adults. Therefore, the interaction between intermittent fasting and exercise training may have potentiated hormonal effects of insulin metabolism, as supported by the findings obtained for the ET and ETI groups. Figure 2 – Area under the glucose tolerance curve (AUC), according to condition and dietary intervention. (A) Individual effect of intermittent fasting; CT: groups submitted to control diet; IF: groups submitted intermittent fasting; *p<0.05 vs. CT. (B) Combined effect. Control: sedentary rats receiving the control diet ad libitum; IF: sedentary rats undergoing intermittent fasting; ET: rats exercising and receiving the control diet ad libitum; ETI: rats exercising while intermittent fasting; † p<0.05 vs. ET. (C) Individual effect of physical exercise training. SD: sedentary groups; ET: exercised groups Two-way ANOVA and Student-Newman-Keuls test. 188