Stress as a causative factor of essential hypertension and its influence on the cardiovascular system.
Cardiovascular responses to cold stress were investigated in hypertensive patients. There were few differences in the changes under cold stress of the serum catecholamine concentration between the juvenile group and middle-aged group. In the juvenile group, a remarkable increase in TPR was observed under cold stress, suggesting that the vascular reactivity is increased and at the same time the cardiac response to inotropic action was increased under cold stress. On the contrary, in the middle-aged group, there was less increase in TPR under cold stress and no increase in inotropic action was observed. From such results, hyperreactivity to stress in the cardiovascular system is thought to be an important factor in the pathogenesis of essential hypertension. Such cardiovascular responses are seen more easily in juvenile hypertension or initial stage of essential hypertension. In the hypertensive patients after middle-age, organic changes will develop by the repeated pressure load to the cardiovascular system caused by various stimulations and the reactivity of cardiovascular system to stress becomes less manifest.