Intermittent fasting associated with aerobic exercise improves oxidative parameters and causes muscle damage without compromising the performance of Wistar rats.

OBJECTIVES: The aim of this study was to` investigate the effects of intermittent fasting (IF) and the possible association with aerobic exercise on performance, oxidative, biochemical, and somatic parameters of Wistar rats. METHODS: Forty rats were randomized into the following groups: sedentary (SC) and trained (TC) controls, sedentary intermittent fasting (SIF), and trained intermittent fasting (TIF). The rats were subjected to IF for 15 h every day and aerobic exercise lasting 30 min, five times a week, at a speed of 15 m/min for 4 wk. Performance tests were performed at the beginning and end of the protocol. Glucose and insulin tolerance, somatic parameters, lipidogram, leptin, insulin, malondialdehyde, antioxidant capacity, C-reactive protein, alpha acid glycoprotein, creatine kinase, lactate dehydrogenase, and muscle histology were analyzed. RESULTS: The trained groups had similar performance and significantly improved performance at the end of the experiment. TIF showed lower body weight (-16 g), lean mass (22.49%), homeostatic model assessment for insulin resistance (29%), and lactate dehydrogenase (48%), and higher malondialdehyde (53%) and antioxidant capacity (75%) than the TC group. The SIF and TIF groups showed a fiber area reduction and positivity marking for tumor necrosis factor-α in the muscles. CONCLUSION: Although IF associated with aerobic exercise improved antioxidant capacity caused damage to muscle fibers and lean mass loss, it did not change the performance of the rats.