|Budget Amount *help
¥4,700,000 (Direct Cost : ¥4,700,000)
Fiscal Year 1991 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1990 : ¥3,700,000 (Direct Cost : ¥3,700,000)
To know workers and/or predictors of hypertension before its' onset in normal young persons with the genetic disposition, the present study has investigated relations between arterial blood pressure responses to mild exercise, maximum aerobic power, and reflexes of high- and low-baroreceptors in human subjects.
In 1990, a main work was on establishing indirect (bloodless) methods how to make separately and simultaneously stimulating high-baroreceptors in the carotid sinus and low- baroreceptors in the cardio-pulmonary part. Another was how to decide characteristics of subjects selected. The practical studies have been performed according to following themes ; 1. as methodological studies, A. developing a system stimulating the high-baroreceptors, B. basal investigation determining pressure loads on the high- and low-baroreceptors, C. realm selecting subjects, and 2. as knowing blood pressure responses to upright exercise, A. blood pressure responses to exercise increasing with step-by-s
tep loads in healthy young persons with the disposition, B. effects of physical training on blood pressure responses to rest and exercise, C. effects of life styles on blood pressure responses to rest and exercise in middle aged persons with the disposition. Depending on the results in the studies, it has been concluded that the upper-limit of lower body negative pressure load to stimulate baroreceptors in cardio-pulumonary part is a -40mmHg, upper-limit of neck suction pressure to stimulate baroreceptors in carotid sinus is a -50mmHg, a load in mild upright exercise is a 50watts, and the subjects would exclude any persons who had higher % body fat or higher maximum aerobic power than the levels in normal healthy persons even though they held the genetic desposition of hypertension.
In 1991, followed in the conclusions given by the previous studies, two studies have been performed ; 1. changes in awakening blood pressure and heart rate during 10 days bed-rest in normal healthy young persons with genetic disposition with hypertension, and 2. arterial blood pressure responses during mild upright exercise and sensibilities of high- and low-baroreceptors reflexes in the young persons. In the studies, it has been found that in normal healthy persons with the disposition the blood pressure response to mild upright exercise is higher, and the inhibitory effect of low-baroreceptors in the cardio-pulmonary part on regulating sympathetic nervous activity is stronger as compared with young persons without the disposition, but the the effect of high-baroreceptors in the carotid sinus is similar. Less