Ventilatory and heart rate responses to hypoxia in well-trained judo athletes

Twenty-four active judo athletes were examined by an isocapnic progressive hypoxia test. 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 observed ventilation and heart rate, VO and HRO the horizontal asymptote in ventilation and heart rate for infinite end-tidal PO2 (PETO2), AVE and AHR the slope constant indicating the magnitude of hypoxic sensitivity, and CVE and CHR the vertical asymptote in PETO2 for infinite ventilation and heart rate. AVE was further re-calculated after VE was normalized for a 70 kg body mass, using an allometric coefficient, and was defined as AVEN. 1) AVE and AVEN significantly increased with increasing body weight (BW) as has been reported previously, but no such correlation was found between AHR and BW. 2) VO2 at rest was found to be positively correlated with AVE and AVEN but not with AHR. 3) The relationship between AVE and AHR was not significant. Thus, the characteristic feature seen in hypoxic ventilatory activity was not accompanied by a similar trend in heart rate response.