Spontaneous wheel running attenuates cardiovascular responses to stress inrats

We investigated the effect of chronic, 10-week spontaneous wheel running (S WR) exercise on stress induced cardiovascular responses in free-moving male rats, using a biotelemetry system. During cage-switch stress or immobiliza tion stress, blood pressure and heart rate were significantly increased in both the SWR (P<0.001 for each stress) and control groups (P<0.001 for each stress). However the blood pressure response was attenuated significantly in the SWR group (P<0.001) during cage-switch stress, and the blood pressur e and heart rate responses were attenuated significantly in the SWR group ( P<0.0001 and 0.01, respectively) during immobilization stress. The plasma n orepinephrine (NE) response induced by immobilization stress tended to be a ttenuated in the SWR group, but the groups showed no significant difference s in the plasma NE and epinephrine (E) responses to both stresses. These re sults suggest that daily SWR in rats has beneficial effects in suppressing excessive blood pressure and heart rate responses induced by two different types of stress. The mechanisms responsible for the greater resistance to t hese stresses in the SWR rats should be investigated further.