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

Summary

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,$\dot V$ _E=$\dot V$ _o+A _VE /($P_{ETO_2 }$−C _VE ) andHR=HR _O+A _HR /($P_{ETO_2 }$−C _HR ), respectively, where$\dot V$ _Eand HR are observed ventilation and heart rate,$\dot V$ _O andHR _O, the horizontal asymptote in ventilation and heart rate for infinite endtidal$P_{O2} \left( {P_{ETO_2 } } \right)$,A _VE andA _HR the slope constant indicating the magnitude of hypoxic sensitivity, andC _VE andC _HR the vertical asymptote in$P_{ETO_2 }$ for infinite ventilation and heart rate.A _VE was further re-calculated after inline_E was normalized for a 70 kg body mass, using an allometric coefficient, and was defined asA _VEN . 1)A _VE andA _VEN significantly increased with increasing body weight (BW) as has been reported previously, but no such correlation was found betweenA _HR and BW. 2)$\dot V_{{\text{O}}_{\text{2}} }$ at rest was found to be positively correlated withA _VE andA _VEN but not withA _HR . 3) The relationship betweenA _VE andA _HR was not significant. Thus, the characteristic feature seen in hypoxic ventilatory activity was not accompanied by a similar trend in heart rate response.