High- and moderate-intensity training are equipotent in abrogating myocardial inflammation in rats fed aWestern diet

Introduction: Western diet (WD) activates inflammatory pathways in the myocardium, where jeopardizes contractile function. This study aimed to compare the anti-inflammatory effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) in rats fed a WD. Methods: Wistar rats were assigned to the six groups: normal diet (ND)+HIIT, WD+HIIT, ND+MICT, WD+MICT, sedentary fed a ND or WD (SED+ND and SED+WD, respectively). HIIT and MICT were performed on a motorized treadmill, five consecutive days/week for 12 weeks. In these animals, visceral fat mass and myocardial expression of pro-inflammatory cytokines i.e. tumor necrosis factor-alpha (TNF-α) and myeloperoxidase (MPO) were measured. Western blotting was performed to identify cardiac protein expression. Results: WD+SED significantly increased visceral fat mass compared with ND+SED. WD+SED significantly resulted in TNF-α over-expression compared with ND+SED. There were no significant differences in MPO expression between WD+SED and ND+SED. In trained groups, visceral fat mass and TNF-α expression were lower in WD+HIIT and WD+MICT compared with WD+SED, with similar effects between HIIT and MICT modes. MPO expression was significantly lower in ND+HIIT and ND+MICT compared with ND+SED, with similar effects between HIIT and MICT modes. Conclusion: WD co-existing with SED paves the way to a pro-inflammatory milieu in the heart. HIIT and MICT exert similar anti-inflammatory effects on the myocardium; therefore, aerobic training, regardless of modality or intensity, can be a practical solution for those who regularly consume WD.