Abstract: AIM To explore the effect of aerobic exercise on cardiac inflammation in spontaneously hypertensive rats (SHR) and the underlying mechanisms. METHODS Sixteen 8-week-old male SHR and 16 age-matched male normotensive Wistar-Kyoto (WKY) rats were randomly divided into SHR exercise group, SHR rest group, WKY exercise group and WKY rest group. Rats in exercise groups were subjected to an 8-week free-of-loading swim training session (1 h/day, 5 days/week). Cardiac functions were monitored by echocardiogram and the levels of TNF-α and IL-1β were determined by ELISA. FoxO1, p65 NF-κB, phosphorylated and total Akt were determined by Western blot analysis. RESULTS The ratio of phosphorylated Akt/total Akt was lower and the levels of FoxO1, p65 NF-κB, TNF-α and IL-1β were higher in SHR rest group than those in WKY rest group, whereas no difference of cardiac functions was observed between the two groups. Eight-week free-of-loading swim training increased the ratio of phosphorylated Akt/total Akt, reduced FoxO1 and p65 NF-κB expression and attenuated levels of TNF-α and IL-1β in SHR. Moreover, 8-week free-of-loading swim training also increased the ratio of phosphorylated Akt/total Akt and reduced FoxO1 expression in WKY rats. CONCLUSION Aerobic exercise significantly attenuates cardiac inflammation in spontaneously hypertensive rats, which may result from the increase in phosphorylated Akt and decrease in FoxO1 expression.