Abstract des Autors

The regulation of pulmonary ventilation is modified by the occurrence of metabolic acidosis during muscular exercise in anaerobic conditions. We evaluated 12 athletes, trained to endurance exercise, and a group of 10 normal subjects, as control. All the subjects underwent a triangular and incremental (25 watt/min) exercise test on cycloergometer. A blood sample was drawn each minute, from an indwelling catheter in radial artery. It was analyzed for pH, and lactic acid (LA). At the same time the ergospirometric data (such as ventilation VE, oxygen consumption VO2, CO2 production VCO2, heart rate HR) were collected each 15 sec.. Furthermore the inspiratory central drive with the P0,1 method was measured. The data analysis may suggest the following considerations: a) in the aerobic phase the athletes have a reduced ventilation and inspiratory central drive, in comparison with controls; b) in the anaerobic phase, despite a similar behaviour of central drive and VCO2, the athletes have a reduced ventilation; c) this may allow a better performance in terms of ventilatory efficiency, the intrinsic mechanism remaining unknown; d) a better tolerance of high lactate levels and an increased possibility of muscular work rate are so possible in athletes. Verf.-Referat