Postural changes associated with public speech tests lead to mild and selective activation of stress hormone release

We tested whether simulation of postural changes, which occur during public speech test procedures, activates cardiovascular system and stress hormone release that could interfere with the effect of psychosocial stress load. Young healthy male volunteers (n=8) underwent procedure imitating exactly all postural changes present in the psychosocial stress model based on public speech used in this laboratory (namely changes from sitting to standing and repeated sitting). Postural changes were associated with increases in heart rate, blood pressure, plasma concentrations of noradrenaline and aldosterone and elevation in plasma renin activity. In contrast to cardiovascular parameters, adrenocorticotropic hormone, cortisol and adrenaline, the main characteristics of hormonal response during mental stress, were not significantly influenced. The overall magnitude of all observed alterations was much smaller than that seen following mental stress procedures in our previous studies. This study provides evidence that changes in body posture during public speech test procedure influence hemodynamics and endocrine responses in a mild manner. Though this influence may represent a source of unspecific variance, substantial confounding effects on responses to the psychosocial component of the procedure are unlikely. In any case, models combining mental stressors and changes in body posture must be interpreted as complex stress stimuli.