The effects of physical training on body weights, succinate dehydrogenase (SDH) activities, norepinephrine (NE) concentrations were examined in the Spontaneously Hypertensive (SHR) Rats. Nine week old animals were trained either by forced treadmill running (26.8m/min; 1hr/day) or voluntary exercise in running wheels (@9,000m/day) for 12 weeks. male rats subjected to forced treadmill running program gained weight significantly more slowly than sedentary controls (p<0.01). SDH activities of the soleus muscle were 30% greater (p<0.01) for the forced exercise animals than the sedentary controls. But, there was no difference between the voluntary exercise and sedentary control groups. Changes in muscle oxidative enzyme activity was used to verify that the forced running exercise had produced an aerobically trained state. Blood pressure (BP) of voluntarily exercised SHR rats was 10% less at 15 wks (p<0.05) and remained lower until the end of training session than that of sedentary control group, whereas BP of forced-trained group was not lowered. The NE concentration of heart in forced-trained group was @12% higher than both of voluntary exercise and sedentary control groups. The results of this study indicate that physical endurance training can depress the blood pressure of SHR rats. However, difference between two types of training suggests that high intensity of endurance training may not be a primary factor to delay the onset of the hypertension.

DESCENTE SPORTS SCIENCE Vol.1/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE