Abstract:In order to investigate the sympathetic nervous function of the aged, the skin potential reflex (SPR) and serum dopamine‐β‐hydroxylase activity (SDBH) were examined in 25 healthy aged and 25 healthy young subjects. In the case of the SPR, the reflex to sound stimuli was analyzed and the following results were obtained: (1) the aged group habituated more rapidly than the young group, (2) the amplitude of the SPR in the aged group was lower than that of the young, and (3) the negative wave of the SPR appeared more dominantly in the aged than in the young group. These results indicated that the sympathetic activation level of the aged decreased in comparison with that of the young. On the other hand, SDBH showed no difference between the aged and young. This discrepancy between the SPR and SDBH is discu