Evaluation of the Autonomic Neuropathy Function Immediately after a change to Upright Posture using the Impulse Response Function

Abstract

The immediate change in heart rate after the change to the upright posture is an indicator of autonomic neuropathy. The subjects are loaded with orthostatic stress. In this paper, we analyzed the correlation between the impulse response function derived from the time series of the R-R interval before postural change to the upright posture and the immediate change in heart rate after a change to the upright posture. We analyzed the postural changes from the supine to the standing position and from the sitting to standing position of healthy men, the postural change from the sitting to the standing position of a healthy young pregnant woman and the postural change from the squat to the standing position of college athletes. The impulse response function derived from the R-R interval time series before the postural change was closely correlated to the decrease in R-R interval with standing. The impulse response function could indeed serve a measurement without orthostatic stress.