DIFFERENTIAL BETA-ADRENERGIC AND ALPHA-ADRENERGIC ACTIVATION DURING PSYCHOLOGICAL STRESS

The responsivity of several cardiovascular indices to a computerized m ental arithmetic stress and a cold presser stress were investigated in 22 healthy adult subjects. The major findings were that the largely b eta-adrenergically driven T-wave amplitude, pre-ejection period, R-wav e to pulse interval, and left ventricular ejection time values respond ed only to mental arithmetic; a significant decrease in cardiac output and increase in peripheral resistance were elicited during the cold p resser test; inter-beat-interval and subjective stress ratings respond ed significantly to both stresses compared to baseline levels, but mor e intensely to mental arithmetic than the cold presser test; blood pre ssure, stroke volume and the maximum of the first derivative of the ra w impedance signal responded unspecifically to both stresses. These fi ndings support the idea that cardiovascular responses to psychological challenge depend on the level of cognitive processing required for th e task. In addition, the superfluity of multiple variable measurements to study cardiovascular reactivity in such situations is discussed.