SPECTRAL CHARACTERISTICS OF SKIN TEMPERATURE INDICATE PERIPHERAL STRESS-RESPONSE

High-resolution measurement of skin temperature in II normal subjects revealed low-amplitude temperature oscillations (40 x 10(-3) degrees C ). The temperature signal measured on two hands during baseline, stres s, and recovery periods, was filtered to separate the low-amplitude os cillations fi om the temperature signal. Spectral analysis of the filt ered signal showed that most of the energy of the signal is in a range of 0.01 to 0.03 Hz. Frequency shifts and amplitude changes of the lar gest component were observed in response to mental stress. In subjects with high baseline values of either of these two variables, a decreas e was observed in response to stress. An opposite response was observe d in subjects with significantly lower baseline levels. Stress-related changes in peak frequency ranged from -25% to +18.2%; changes in peak amplitude ranged from -74.6% to +280%. Changes in the mean temperatur e were limited to 2.4%. Thus, the oscillatory component showed higher sensitivity to psychological stress than mean temperature. The spectru m of this component was compared to the spectrum of the blood pressure waves measured noninvasively. Both exhibited similar dynamics of ener gy peak amplitude, and peak frequency in response to psychological str ess. This similarity suggests that the oscillatory temperature compone nt reflects stress-related changes of peripheral vasomotor activity.