Sympathetic indices during psychological and physical stimuli before and after training

The effects of psychological and physical stimuli on cardiovascular and catecholamine changes were studied before and after physical training. These functions were investigated in eight labile hypertensive men in response to the mild psychological stimulus of playing a video game and the mild physical stimuli of sitting and standing. The results show that plasma norepinephrine concentration rises with sitting and standing but plasma epinephrine concentration increases only with the psychological stimulus. Physical training was associated with smaller increases in blood pressure during psychological and physical stimuli and with a lower heart rate at rest. On the other hand, plasma catecholamines at rest as well as in response to the different stimuli were unchanged following moderate training. These observations suggest that the adrenal medulla is selectively activated during a period of mild psychological stress, while the activity of the sympathetic fibers is preferentially increased during mild physical stimuli. Furthermore, the results of this study show that plasma catecholamine levels at rest and their increase during various stimuli are unchanged following training.