FAMILY HISTORY OF HYPERTENSION, EXERCISE TRAINING, AND REACTIVITY TO STRESS IN RATS

In this study we sought to assess the role of exercise training on blo od pressure (BP) reactivity to tailshock stress in rats with varying f amily histories of hypertension. Exercise training consisted of swimmi ng 90 min per day in isothermic water for either 2, 6, or 10 months, b eginning at 2 months of age. Control subjects were age-matched and did not exercise daily. Rats with either zero (Wistar-Kyoto), 1 (borderli ne hypertensive), or 2 (spontaneously hypertensive) hypertensive paren ts were studied. At the appropriate age, femoral artery catheters were implanted and rats were studied at rest and in response to a 20-min s tress session. Exercise training reduced basal BP, especially in rats with a positive family history that were exercised for the longest dur ation. Reactivity to stress was actually significantly enhanced in tra ined rats. Thus, these data do not support the reactivity hypothesis, but suggest several reasons why the literature has been so inconsisten t. The discussion emphasizes the importance of basal, rather than phas ic, BP responses resulting from exercise training.