Intermittent Fasting Attenuates Exercise Training-Induced Cardiac Remodeling

BACKGROUND: The effects of non-pharmacological interventions such as calorie restriction and exercise training on health and prevention of cardiovascular diseases have been investigated in clinical and experimental studies. OBJECTIVE: To analyze the influence of intermittent fasting and exercise training on functional fitness, glycemia and cardiac remodeling. METHODS: Wistar rats (n=60) were randomly divided into four groups: control, exercise training (ET), intermittent fasting (IF) and exercise training plus intermittent fasting (ETI). Over 12 weeks, control and ET animals were fed daily a standard commercial diet ad libitum , while IF and ETI animals were fed every other day. In addition, the ET and ETI groups were submitted to a running protocol on a treadmill. After this period, functional fitness, nutritional parameters and blood glucose levels were analyzed. In addition to heart morphology, myocardial protein expression of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was assessed by Western-blot. The results were analyzed using two-way ANOVA and Student-Newman-Keuls test. The level of significance considered was 5%. RESULTS: Exercise training increased functional fitness in the ET and ETI groups and promoted cardiac fibrosis. The combination of intermittent fasting and exercise training resulted in a smaller area under the blood glucose curve and reduced cardiomyocyte cross-sectional area and interstitial collagen fraction in the ETI group compared to ET. ERK and JNK expression levels were similar among groups (p>0.05). CONCLUSIONS: Intermittent fasting is associated with improved glucose tolerance and attenuates cardiac remodeling induced by exercise training (Arq Bras Cardiol. 2020; 115(2):184-193).