THE RELATIONSHIP BETWEEN TEST PROTOCOL AND THE DEVELOPMENT OF EXERCISE-INDUCED HYPOXEMIA (EIH) IN HIGHLY TRAINED ATHLETES

Healthy male endurance-trained cyclists [n = 11, age = 27.3 (3.9) year s; mass = 73.0 (9.3) kg; height = 180.5 (6.9) cm; maximal oxygen consu mption (VO2max) = 71.1 (5.8) ml . kg(-1). min(-1): mean +/- (SD)] were recruited to assess the relationship between test protocol and the de velopment of desaturation of arterial hemoglobin with oxygen, during i ncremental exercise tests to maximal aerobic capacity (VO2max). All su bjects demonstrated resting pulmonary function within normal limits [f orced vital capacity (FVC) = 6.0 (0.9); forced expiratory volume (FEV( 1.0)) = 4.9 (0.6); FEV(1.0)/FVC = 0.8 (0.1)] and completed three rampe d VO2max tests (Mijnhardt KEM-3 electronically braked cycle ergometer) beginning at 0 W with increments of either 20, 30 or 40 W . min(-1). All periods of testing were separated by a minimum of 72 h. VO2max, pe ak minute ventilation (V-Epeak) (Medical Graphics, CPX-D), peak heart rate (f(cpeak)), peak power output (W-peak), and minimum percentage ar terial oxyhemoglobin saturation (%SaO2min) (Omeda Biox 3740 pulse oxim eter) were determined. There were no significant differences (p > 0.05 ) in V-Epeak [191.5 (26.2), 196.0 (24.4), 194.3 (23.9) l . min(-1)] f( opeak) [191.4 (7.0), 190.3 (5.5), 187.8 (5.9) beats . min(-1)], VO2max [5.0 (0.5), 5.1 (0.4), 5.1 (0.5) l . min(-1)] or %SaO2max [89.5 (1.5) , 89.6 (1.3), 90.0 (2.3)] between protocols. The 20-W protocol [417 (2 7) W] demonstrated significantly lower W-peak (P < 0.05) than the 30-W [434 (36) W] and 40-W [453 (38) W] protocols, indicating that periphe ral fatigue may play an important factor in response to these tests. T he results of this study demonstrate that arterial desaturation occurs as a result. of intense exercise in highly trained athletes independe nt of the rate of attainment of VO2max.