[A study on the primary prevention of essential hypertension (1). Evaluation of blood pressure response during exercise and effect of habitual exercise].

Hypertension is one of the risk factors of cardiovascular diseases, which are widely prevalent maladies that result in burdensome medical expenditures. Therefore, it is important to explore primary preventive measures for hypertension. Until recently, it was thought that exercise was a risk factor for hypertension, but recent reports have suggested that low-intensity physical training actually lowers blood pressure. However, habitual physical exercise has still not been clearly proven to prevent the development of hypertension. To clarify this point, one must first establish a method for predicting hypertension and second examine the possibility of preventing the development of hypertension by changing the subject's environment. In this study we have investigated a method for predicting hypertension by classifying blood pressure responses to increasing exercise intensity and the effect of habitual exercise on blood pressure response. This study was composed of three experiments. Experiment one involved female students (n = 42) and experiment two, male students (n = 38), in whom blood pressure response rates during exercise were recorded. In experiment three, the same group of female students (n = 23) was subjected to training in order to chart its effects on blood pressure response, both while exercising and while at rest. The exercises were performed with a bicycle ergometer in an upright position. There were four different degrees of work intensity. Blood pressure was measured using the auscultation method, with Riva-Rocci mercury measured by the same investigator. High blood pressure responses at rest were noted among some normotensive female and male students. The systolic blood pressure responses during the peddling exercise showed significant individual differences at the lowest work load; the distribution of the increment of the systolic blood pressure ratio at the lowest work load against the increment while resting showed two peaks. This result suggests that this increment ratio is an important variable related to the prediction of hypertension. The increment ratio showed no significant change in female students after three months of aerobic exercise. The high-response group showed high readings of the TPR indicator (MBP/VO2). Aerobic training was shown to be effective in significantly lowering the TPR indicator both at rest and during exercise. This result suggests that habitual exercise may contribute to preventing the development of hypertension.