Cardiovascular parameters after diverse conditions of stress and rest.

Twenty-one volunteers were subjected to the following conditions: rest, cold pressor, a very difficult word completion task, progressive relaxation, physical effort, and lastly, a further rest period. Dependent variables were: Pulse Transit Time (PTT), Inter Beat Interval (IBI) and the first derivative Ear Densitogram Ejection Time (dEDET). The three variables show a convergent reaction pattern, as expressed by Kendall's coefficient of concordance W, which showed a median value of .72. PTT appeared to be the most sensitive parameter, whereas dEDET was the least sensitive one. The outcome of the decision-tree mostly pointed to a decrease (35%) or increase (27%) in beta-adrenergic activity. This was generally accompanied by an increase or decrease of dEDET, respectively.