Urinary excretion of adrenaline and noradrenaline during prolonged immobilization.

Ss who successfully completed 1 wk. of immobilization showed no significant changes in subjective stress and mood or in the urinary excretion of adrenaline and noradrenaline (catecholamines) relative to recumbent controls. On the other hand, the catecholamine excretion of the immobilization quitters was related to their endurance. The early quitters showed no significant changes, whereas the late quitters showed an increase, particularly in adrenaline excretion. Another characteristic of the quitters was the presence of a lower base-line level of adrenaline, relative to successful Ss and recumbent controls, not only prior to immobilization but also 2 mo. after its termination. Unfortunately, the results only bordered on statistical significance. A striking similarity was noted between these results and those obtained in an earlier study involving 1 wk. of perceptual isolation.