Effect of Different Exercise Modes on Aldosterone and Sodium Retention in Rats with Myocardial Infarction

After myocardial infarction (MI), cardiac remodeling activates Renin‐Angiotensin‐Aldosterone system (RAAS), which causes sodium (Na + )‐induced plasma expansion, a contributor to ventricular dilation. Evidence suggests Post‐MI exercise training preserve cardiac function by attenuation of RAAS. However, the effects of different exercise modes, endurance (END) versus strength (ST) training, on ALD and Na­ + in the post‐MI heart have yet to be investigated. The aim of this study was to explore the effects of ST versus END on ALD and Na + in rats with MI. MI was surgically induced in 7‐wk‐old rats by ligation of the left anterior descending coronary artery, with sham‐operated animals serving as controls. The survivors were assigned to 4 groups: Sham (n=9,), MI+SED (n=9, MI+no exercise), MI+END (n=7), and MI+ST (n=10). One wk after surgery, MI+END were trained on a rodent treadmill (at 16m/min, 5 0 incline, 40min/d, 5d/wk) and MI+ST were trained on a ladder with weight attached to tail (1 m high, step loading periodization, 3d/wk) for 10 wks. Our results showed that there was no difference (P>0.05) in ALD between MI+END (605±40 pg·mL ‐1 ) and MI+SED (656±31), but both were significantly (p<0.02) greater than MI+ST (483±19). Similarly, there was no difference (p>0.05) in plasma Na + concentration (mMol·L ‐1 ) between MI+END (187±3) and MI+SED (179±0.4), However, both were significantly greater (p<0.002) than MI+ST (170±4). Our data suggest that compared to MI+END, MI+ST may favorably attenuate RAAS activity and Na + retention after MI.