Electrodermal lability and hypertension

Thirty-nine (39) middle-aged subjects with mild to moderate hypertension (WHO stages I-II) and 35 healthy normotensive controls from a community sample participated in this psychophysiological study, the aim of which was to study whether the electrodermal lability as an indicator of increased sympathetic activity is related to hypertension. Resting blood pressure was measured by using a mercury sphygmomanometer. Electrodermal activity was recorded with a constant voltage circuit. Bipolar skin electrodes were placed on the palmar side of the middle phalanges of the index and middle fingers of both hands. Six years after the electrodermal measurements, the possible use of reimbursed antihypertensive medication was checked in both groups, and blood pressure re-measured in the control group. Multivariate analysis controlling for age, gender and body mass showed that the electrodermal lability was increased in the hypertensive as compared to the normotensive group. This supports the hypothesis that the sympathetic nervous system tonus is increased at least, in some middle-aged subjects with mild to moderate hypertension.