Comparison of ventilatory and heart rate responses to hypoxia at rest and during light exercise in high school judo athletes.

Ventilatory and heart rate responses to hypoxia at rest and during light exercise (30W) were compared in 21 high school judo athletes. The results of ventilatory and heart rate responses to hypoxia were analyzed by the hyperbolic equations, VE = VO + AVE/(PETO2-CVE) and HR = HRO + AHR/(PETO2-CHR), respectively, where VE and HR are the observed ventilation and heart rate, VO and HRO the horizontal asymptote in ventilation and heart rate for infinite endtidal PO2 (PETO2), AVE and AHR the slope constants indicating the magnitude of hypoxic sensitivity, and CVE and CHR the vertical asymptote in PETO2 for infinite ventilation and heart rate. AVE was further recalculated after VE was normalized for a 70 kg body mass, using an allometric coefficient, and was defined as AVEN. The absolute magnitudes of hypoxic response in ventilation and heart rate at PETO2 40 mmHg were also determined as delta V40 = AVE/(40-CVE) and delta HR40 = AHR/(40-CHR), respectively. (1) The enhanced hypoxic ventilatory chemosensitivity previously found in heavy-weight judo athletes at rest was confirmed. However this characteristic disappeared with exercise. (2) It was also confirmed that there was no significant correlation between hypoxic heart rate sensitivity and body weight at rest. With exercise, this was found also to be the case. (3) On the other hand, when the hypoxic responses at rest were compared to those of the exercise studies, significant positive correlations were illustrated in both ventilatory and heart rate responsiveness. These results demonstrated that although ventilatory and heart rate responses did not quantitatively exhibit parallel change, the two activities did demonstrate a certain synergism between rest and exercise.