Abstract des Autors

The authors relate a short literature review on the apnea physiological heart adjustment: the Diving Reflex. During apnea an important bradycardia, preserving a good brain and heart perfusion, allow us to save O2 in the tissues, this process is known as Oxygen-Conserving Reflex that seems to be used by the man only in severe status. Furthermore, some components of the Diving Reflex like: heart rate, lung pressure, lung volumes, dissolved gases, autonomic nervous system control, are considered and compared between the man and the dive suited animals. About physical exercise are considered: the outwater, the full or partial underwater, the water temperature apnea effects; these events are compared between rest and different physical activity, in detail synchronized swimming. Some peculiar synchronized swimming physiological events, due to endurance activity and underwater breath-holding, are analyzed. Apnea induced heart-rate variations during the performance of this sport is closely examined. The authors end this short review with some helpful advice for the synchronized swimmers to improve the time of apnea, the underwater bradycardia and to avoid syncope events. Verf.-Referat