Abstract

The Diving Reflex (DR) is a conntant reflex, easily evocable and reproducible, connected with a strong reflexe of vagal nature. The size of heart rate (HR) fall, during test, was influenced by aging and training level, also if in all the subjects selected, a reduction of HR is always significant if compared with basal. Particularly, the authors have observed that in young people, during DR, HR was significantly lesser correlated to training status; on the contrary, in older subjects, in some experimental conditions, HR responses during DR were exactly alike, indipendent of the level of training; in all untrained subjects the bradycardia obtained during DR was significantly greater in the younger subjects than in olders. It is concluded that in young subjects the bradycardic response to DR was antagonized by training effects, and that the sympathetic responsiveness reduction, characteristic of the aging, may play an important role in responses observed in old subjects during DR. This evocation test can find a useful routine application. Verf.-Referat