Family history of hypertension, exercise training, and reactivity to stress in rats

The effects of exercise on haemodynamic function in relation to the familial hypertension risk model

Offspring hypertensives are characterized by a hyperactive sympathetic nervous system and other early cardiovascular abnormalities that increase the risk of developing hypertension. A physically active lifestyle is associated with a lower risk of hypertension, although the mechanisms are incompletely understood and likely to be multifactorial. One aspect that has received little attention is the interaction of exercise with familial hypertension risk. The present review examines the effects of exercise on haemodynamic function in relation to the familial hypertension risk model. Paradoxically, exercise may be viewed as potent stressor to the cardiovascular system, although recent studies are beginning to show that cardiovascular adaptations, primarily mediated by changes in sympatho-vagal balance, following both acute and chronic exercise may be particularly important for individuals with familial risk of hypertension. Future studies that focus on inflammatory, metabolic, and genetic pathways may uncover further beneficial effects of exercise in relation to familial risk.

Effect of exercise training on liver antioxidant status of deoxycorticosterone acetate salt induced hypertensive rats

Several animal models have been developed to study the pathogenesis of hypertension. Deoxycorticosterone acetate (DOCA) salt induced hypertensive rats are adrenal models used to mimic human Conn's syndrome. Because previous studies showed a beneficial effect of chronic exercise (swimming) on the development of arterial hypertension in spontaneously hypertensive rats (which appears similar to human essential hypertension), we decided to evaluate the effects of swimming on DOCA-salt induced hypertension and liver antioxidant status. Therefore, the aim of this experiment was to study whether the swim training would improve hypertension and liver antioxidant status in DOCA-salt rats. DOCA-salt rats and control Sprague-Dawley rats were trained to swim 1 h/day, 5 days/week for 6 weeks and were sacrificed 48 h after the last exercise period. Systolic blood pressure was recorded before the sacrifice, and liver antioxidant status was evaluated in hepatic homogenates after the sacrifice. Swim exercise did not decrease systolic blood pressure in control and DOCA-salt rats but induced changes in liver activities of antioxidant enzymes, showing that exercise provoked liver oxidative stress in control and DOCA-salt rats. In comparison with our previous studies using spontaneously hypertensive rats, we conclude that the beneficial effects of chronic exercise on systolic blood pressure in rats are dependent on strain and the type of experimental hypertension.