Experiments were performed to test the postulate that exercise training (ExT) improves the blunted renal excretory response to acute volume expansion (VE) in part by normalizing the neural component of the volume reflex typically observed in chronic heart failure (HF). Diuretic and natriuretic responses to acute VE were examined in sedentary and ExT groups of rats with either HF or sham operated controls. Experiments were performed in anesthetized (Inactin) rats 6 weeks after coronary ligation surgery. In sedentary rats with HF, VE produced a blunted diuresis (46% of sham) and natriuresis (35% of sham). However, acute VE induced diuresis and natriuresis in ExT rats with HF were comparable to sham rats and significantly higher than sedentary HF rats. Renal denervation abolished the salutary effects of ExT on renal excretory response to acute VE in HF. Since glomerular filtration rates were not significantly different between the groups, renal hemodynamic changes may not account for the blunted renal responses in HF rats. Additional experiments confirmed that the renal sympathetic nerve activity (RSNA) responses to acute VE were blunted in sedentary HF rats however, ExT normalized the renal sympatho-inhibition in HF rats. These results confirm an impairment of neuronal mediated excretory responses to acute VE in HF. ExT restored the blunted excretory responses as well as the renal sympatho-inhibitory response to acute VE in HF rats. Thus, the beneficial effects of ExT on cardiovascular regulation in HF may be partly due to the improvement of the neural component of the volume reflex.