Vasomotor Response of Non-Hypertensive Individuals to a Standard Cold Stimulus

Abstract

Hines and Brown 1 have described a standard test for the study of vasomotor reactions based on the responses of the blood pressure to a cold stimulus. They are of the opinion that “excessive” responses to this test indicate a hypersensitive sympathetic nervous system. Assuming that the principal abnormality in essential hypertension is a hypersensitive sympathetic nervous mechanism, they have considered non-hypertensive individuals with “excessive” responses potential candidates for hypertension. They suggest that essential hypertension develops only in individuals manifesting “excessive” responses; that these abnormal responses depend upon an hereditary factor, and that they appear early in life. If these theories are correct, it is apparent that in advanced age periods where actual essential hypertension has already developed in many of the potential hypertensives, there should be a lower percentage of “excessive” responses in the individuals of the same age period with normal blood pressures. Also, it would follow that the average response of non-hypertensive people in the advanced age periods would be lower than the average response of non-hypertensives in younger age groups.

It is the purpose of this study to investigate the incidence of “excessive” responses in a group of non-hypertensive subjects; and, to compare the average response of this group with the series reported by Hines and Brown. 2

Two hundred and five subjects with a systolic blood pressure below 140 mm. Hg. and a diastolic blood pressure below 90 mm. Hg. have been chosen at random. The ages of the individuals selected have varied from 8 to 70. Each subject has been tested according to the technic described by Hines and Brown. 1

The upper limit of normal response was first arbitrarily placed by Hines and Brown 1 at 15 mm. Hg., but in a subsequent publication 2 they raised their limit of normal to 22 mm. Hg.