The effects of strength training versus endurance exercise on blood volume expansion in rats with myocardial infarction (706.13)

Abstract

After myocardial infarction (MI), cardiac remodeling causes sodium‐induced plasma expansion (PE), contributing to ventricular dilation. Evidence suggests Post‐MI endurance exercise (END) improves cardiac function (CF). However, it is known that END causes albumin (ALB)‐induced PE, a normal training adaptation. This may not be beneficial to an infarcted heart as it may worsen the MI‐induced PE. In contrast, strength training (ST) may increase myocardial strength without causing ALB‐induced PE. The aim of this study was to investigate the effect of ST versus END on PE in the post‐MI rat hearts. MI was induced by ligating the coronary artery. 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). Exercise training was initiated 1 wk post‐MI on either a rodent treadmill (END) or 85° incline ladder (ST) for 10 wks. Our results showed total blood volume (TBV) and PE (ml·100g‐1) was significantly greater in MI‐END compared to MI‐ST (5.95±0.84 vs. 4.11±0.59, 3.74±0.49 vs. 2.49±0.24, p<0.05). Additionally, ALB concentration (g·dL‐1) was also significantly greater in MI‐END than MI‐ST (4.59±0.52 vs. 2.75±0.28, p<0.001). Our data suggests that compared to END, ST may favorably limit post‐MI TBV and PE.