| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
The present study investigated if cardiovascular responses during static and dynamic exercises might be different between children with hypertensive parents and children with normotensive parents. Twenty healthy females whose parents had been in essential hypertension (H-group) and 20 age-matched normotensive females whose parents were both normotensive (N-group) served as subjects in EXP I.Both groups performed a 2-min sustained static knee extension of which intensity was 30 % of maximal voluntary contraction (MVC). There was no difference between H- and N-groups in body size, body fat, resting arterial mean blood pressure (MAP) , heart rate (HR) , cardiac output (CO) and total peripheral resistance (TPR). Increases of MAP during static exercise in both groups were also identical. However, there were clear differences in component factors of MAP (i.e., CO and TPR). CO during exercise in H-group was significantly lower than that in N-group while TPR in H-group was significantly higher
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than that in N-group. Thus, the increased MAP in H-group was caused by the elevated TPR while that in N-group was induced by the elevated CO.Forearm blood flow and forearm skin blood flow measured during static exercise indicated that vascular beds in skeletal muscles and cutaneous tissues showed identical responses to exercise in both groups. Therefore, the increased TPR in H-group was induced by increased vasoconstriction in vascular beds except for skeletal muscles and cutaneous tissues, which were probably splanchinic and renal beds. In EXP II,different twenty-one females and 18 females respectively served as subjects for H- and N-groups whose age, body size, body fat and resting MAP were identical. Both groups performed a 20-min bicycling exercise of which intensity increased every 5 min. from 20%, 40%, 60% to 80% of maximal exercise (Loadmax). During 60% and 80% Loadmax cardiovascular responses were different between two groups although oxygen consumption was identical in both groups. MAP in H-group increased significantly greater than that in N-group. The increased MAP in H-group during higher intensities was also caused by increased TPR,probably due to greater vasoconstriction in splanchinic and renal vascular beds. These results from EXPs I and II suggest that the cardiovascular responses to both static and dynamic exercises in H-group are different from those in N-group while the subjects in H-group are now healthy and normotensive. Less
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