To study the relationship between performance and exercise-induced arterial hypoxemia (EIAH), 5 internationally ranked (INT) and 8 regionally ranked (REG) triathletes performed cycle-run successions (CR) and control runs (R) in competitionlike conditions: at ≍75% VO2max.
Ventilatory parameters and oxyhemoglo-bin saturation (SpO2) data were collected continuously. Arteriolized partial pressure in O2 (PaO2) and alveolar ventilation (VA) were measured before and after cycling (CRcycle), the successive run (CRrun), and R. Pulmonary diffusing capacity (DLco) was measured at rest and 10 minutes post-CR. Training and short-distance triathlon data were collected.
INT showed signifcantly greater experience than REG in competition years (P > .05), training regimen (P > .05), and swimming (P > .05), and cycling (P > .05) volumes; running showed a trend (P < .06). Cycling, running, and total triathlon performances were significantly higher in INT than REG (P > .01). SpO2 during CR dropped significantly more in INT than in REG. Both groups showed significant inverse correlations between the magnitude of the SpO2 change from CRcy-cle to CRrun and the triathlon running time (r = −0.784; P < .05 and r = −0.699; P < .05; respectively). When compared with CRcycle, PaO2 significantly decreased and VA significantly increased after CRrun and R in both groups (P < .01). DLco significantly dropped between pre- and postexercise in CR and R with no between-group difference (P < .05).
EIAH was aggravated in higher performers during simulated cycle-run segments, related to longer experience and heavier training regimens. Possibly, relative hypoventilation caused this aggravated EIAH in INT, although pulmonary diffusion limitation was observed in both groups. Beyond EIAH severity, the magnitude of SpO2 variations during the cycle-run transition may affect triathlon running performance.
Galy is with Laboratory Actes—Physiology, Noumea, New Caledonia; Hue is with Laboratoire Actes—Life Sciences; Chamari is with the National Centre of Medicine and Science in Sport—Research Unit “Evaluation, Sport, Health”; Boussana is with Université Montpellier 1—Laboratoire de Physiologie des Interactions; Chaouachi is with the Research Unit “Evaluation, Sport, Santé”; and Préfaut is with UPRES-EA 701 “Laboratoire de Physiologie des Interactions”—Service Central de Physiologie Clinique, Centre Hospitalier Universitaire Arnaud de Villeneuve.